Railway Lexicon

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Introduction to the Railway Lexicon

This lexicon was originally produced by the Railway Systems Group at the University of Sheffield in cooperation with Railtrack (now Network Rail) and other organisations. Staff at the University of Sheffield and the team of The Railway Consultancy update the Lexicon on a regular basis. In general, the UK term "railway" is used rather than the US term "railroad". Obsolete Railtrack terminology is shown in brackets where known. The tags at the end of phrases "RT" and "UoS" signify that Railtrack or the University of Sheffield, respectively, contributed the definition. Where definitions vary between sources or additional information is provided two definitions are provided. Comments and feedback are welcomed by: f.schmid@bham.ac.uk

Further information is available at:
The Modern Railway Glossary - The Brakes Glossary - The Steam Locomotive Glossary - The Electric Traction Glossary - Acronyms and Abbreviations - US-UK Terminology

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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A...

Abnormal Heavy Road Load

Any road load which falls outside the scope of the Construction and Use Regulations because of its weight or weight distribution.^RT

Abnormal Road Load Indemnity

A form of indemnity submitted to Network Rail by a road haulier as prescribed in the Motor Vehicles (Authorisation of Special Types) General Order 1979 (as amended).^RT

Abnormal Road Load Notification

A notice submitted to Network Rail by a haulier which gives loading details of a proposed abnormal road load movement, its proposed date and time of travel, and its proposed route.^RT

Absolute Block

A railway signalling system which is based on the principle of dividing a railway line into a sequence of individual sections or blocks, allied to the principle of never having more than one train on the same line in the same section at the same time. The acceptance of a train by the signaller at the signal box in advance is necessary before a train is allowed to proceed into the Absolute Block Section.^RT

Abstract of Particulars

A subsection of the contract conditions which contains routine details relevant to that specific contract.^RT

Acceptable Quality Level

A value which limits the number of contract checks which are permitted to fail within a predetermined sample (e.g. an AQL of 1.0 indicates that no more than 1.0% of the checks will be permitted to produce a fail without a tightening of the inspection regime.)^RT

Acceptance (of rolling stock)

Final part of the process to introduce new types of rolling stock, onboard systems or infrastructure components to the railway network managed by Network Rail.^UoS

Acceptance Manager

The Network Rail manager assigned by the RSAB Group Manager, having responsibility for managing the process for a route acceptance request. The Acceptance Manager will be the Network Rail principal point of contact on noncommercial matters to the applicant.^RT

Acceptance Plan

A Network Rail project plan defining Network Rail activities in support of a Route Acceptance Request.^RT

Accepting

UK railway signalling term, 'accepting' refers to the permission given by a signaller for a train to enter the section of line which he or she controls. ^UoS

Access Agreement

An agreement regulated under the Railways Act 1993 setting out the terms and conditions under which companies/operators obtain access to railway track, stations and certain types of depots.^RT

Access Charge

The charge paid by railway operators for access to rail facilities which are the subject of an access agreement.^RT

Access Planning Software

Access planning software system for the planning of track access for both permanent and shortterm train schedules. It replaced PROTIM.^RT

Accident

An unexpected, unplanned occurrence which results in physical harm (injury or disease) to an individual, damage to property, a near miss, a loss, or any combination of these effects. (See also Incident.)^RT+UoS

Accommodation Bridge

A bridge connecting two areas of land which were under common ownership but separated when the railway was built.^RT

Account Executive

The manager responsible for commercial dealings with the Train Operators.^RT

Accounts Payable

A team of people within the finance function responsible for the correct payment of authorised supplier invoices.^RT

Account Receivable

A team of people within finance responsible for the dispatch and credit control of properly authorised invoices to customers.^RT

Activity Based Costing

The process of identifying the costs associated with particular daytoday activities or specific tasks and projects.^RT

Actual Costs

The term used to encompass both costs paid over to suppliers and accruals.^RT

Actual Cost of Work Performed

An assessment of the physical progress on a scheme and its financial value. This will include costs for invoices paid and accruals to repeat bills not yet presented for the actual progress achieved.^RT

Add Value Machines

Used in some automatic fare collection systems to allow passengers to increase the residual value of a stored value ticket.^UoS

Adhesion Coefficient (m)

The ratio of the tangential and normal forces that exist between the wheel and the rail at standstill and during motion. The adhesion coefficient for rolling motion is usually referred to as m _R. Generally taken as 0.3 to 0.4 for dry rail, but can be as low as 0.01 for icy and greasy rail.^UoS

Adjustment Switch

A device which allows longitudinal rail movement to dissipate thermal forces when CWR is adjacent to jointed track or other features not designed to withstand thermal forces. Adjustment switches are also used when thermal forces, additional to those in CWR, may be encountered such as at long underbridges which are themselves subject to expansion and contraction. (US term: Breather Switch.) ^RT

Advanced Passenger Train

High speed tilting train, abandoned in the early 1980s.^RT

Air Rights Development

Property exceeding existing building height constructed on and above land owned by Network Rail.^RT

Airless Spraying

The process of atomisation of paint by forcing it hydraulically through an orifice at high pressure^RT

Alignment

The horizontal (line) and vertical (top) position of a railway track, described by curved track of horizontal radius R, tangent track where R = ¥ , vertical radius and gradient.^UoS

Alley (US)

A clear track in a switching yard. (UK: marshalling yard.)^UoS

Anchor Length

The length of CWR track that is left clipped down during the stressing operation to ensure that no movement occurs at the fixed ends of the length being stressed.^RT

Ancillary Movement

Movements of locomotives and rolling stock directly in association with normal daytoday train services.^RT

Annual Renewal Plan

Plan identifying those assets which were to be renewed by Railtrack in the forthcoming contract year.^.RT

AntiCreeper (US)

A device firmly attached to the base of a rail and bearing against a crosstie (sleeper), to keep the rail from moving longitudinally under traffic. (UK: Rail Anchor.)^UoS

Approved In Principle

Approval in principle signifies that a professionally competent person or body is satisfied that:

a scheme chosen to bring about a change to the infrastructure will meet the requirements of the remit; ^RT
appropriate standards and/or design criteria have been proposed for the design/checking phase.^RT

Area Delivery Group

A zonal team charged with meeting the minutes delay targets by identifying, testing and implementing performance improvements.^RT

Arm Repeater

An electrical indicator which shows the position of a semaphore signal arm to the controlling signalman.^RT

Articulation

The core feature of a rolling stock design where two adjacent railway vehicle ends are mounted on a common bogie. Nowadays much favoured by tramcar or light rail vehicle designers. Also used for some European highspeed train designs, namely, TGV and Eurostar carriages. It has the benefit of reducing the number of bogies required for a train. Generally only suitable for lighter weight vehicles since the load on each axle is proportionately increased. Usually requires that special lifting systems or bogie drop pits are provided in maintenance workshops. ^UoS

Aspect

The visual indication of a colour light (or mechanical) signal as displayed to the driver.^RT

Asset Maintenance Plan

A plan of remedial maintenance work outstanding from the BR maintenance programme prior to creation of Railtrack.^RT

Asset Maintenance Plan Provision

The funding provision provided to Railtrack on company formation to complete the works identified in the AMP.^RT

Asset Management Work Team

The team which led a detailed review of Railtrack’s approach to asset management with the key objective of optimising maintenance and renewal costs.^RT

Asset Related Expenditure

Any expenditure relating to the enhancement or renewal and, for certain asset categories, maintenance of the railway infrastructure and any other assets as per the Capital Accounting Rules. This will include expenditure relating to Capital Enhancement and Renewal Projects, Asset Maintenance Plan and Station Regeneration Programme. Refer to the Railtrack Investment Regulations, Capital Accounting Rules and SRP Financial Guidelines for further information. ^RT

Asset Renewal

Replacement by Network Rail of an existing asset whose maintenance is within the scope of the RT1A contract.^RT

Asset Replacement

Renewal of an asset undertaken by the contractor at no additional cost to the employer.^RT

Associated Society of Locomotive Engineers and Firemen

Union, popularly known as ASLEF, which represents many train drivers.^RT

Authority to Recruit

The approval, by a person with delegated authority, for the recruitment of permanent or agency staff.^RT

Automatic Block Signal (ABS)

A train control subsystem based on a series of consecutive blocks governed by block signals which are controlled by the movement of trains and certain other conditions (e.g., detection of level crossing closure) rather than by a signaller or train describer driven route setting system. The installation includes automatic line side signals, cab signals or both, actuated by a train or light engine by means of axle counters or track circuits. This is a very basic form of automatic route setting (ARS).^UoS

Automatic Cab Signal System (ACS) (US)

A system that automatically operates a display of signal aspects in the cab of a train as well as the cab warning whistle.^UoS

Automatic Code Insertion

The means by which, when a train terminates, the next working of its stock is automatically picked up by the signalling in IECC areas.^RT

Automatic Coupler

An automatic coupler allows two vehicles to be attached to each other merely by pushing the two vehicles together. There are various types and systems in use, which range from a simple automatic mechanical coupler (like the 'buckeye coupler' of US origin) to one which is remotely controlled and can connect and secure air and electrical connections in one operation. In Europe only used for Multiple Unit trains and specialised types of rolling stock. The proposed UIC autocoupler was shelved in the 1970s due to cost but Germany and France are currently carrying out trials of a traction only autocoupler.^UoS

Automatic Dropping Device

Mechanism which causes a damaged or displaced pantograph to drop automatically to limit (further) damage to the overhead line equipment.^RT

Automatic Fare Collection (AFC)

A revenue collection system common on metros and urban railways which requires the passenger to buy a ticket and use it to release an entrance and / or exit gate to permit access to or exit from the railway. AFC reduces the need for ticket checking staff and reduces fraud by passengers and staff. ^UoS

Automatic Level Crossing

Includes AHB, ABCL, AOCL and AOCR level crossings plus those protected by miniature red/green warning lights. ^RT

Automatic Open Crossing (remotely monitored)

Now only one left on the Network Rail system (in Scotland.)^RT

Automatic Railway Inquiry Systems

In Europe a prototype system to provide passenger timetable information.^RT

Automatic Route Setting (System) (ARS)

Electronic or relay based system which sets routes using information from a train describer and the timetable without the need for intervention by a signaller.^UoS

Automatic Signal

A colour light signal which operates automatically as trains travel onto and off track circuits ahead.^RT

Automatic Stop Arm (US)

See Automatic Train Stop (UK).^UoS

Automatic Systems

The hierarchy of the components of automatic assistance to the operation of trains is not clearcut. Different authors advocate different structures. The structure presented in the figure below is based on PhD work by D.Woodland.

Automatic Train Control (ATC)

The system for automatically controlling train movements and directing train operations. ATC requires automatic train operation (ATO) and automatic train protection (ATP) subsystems and has features which enhance operational safety, e.g., through the separation of trains by implementing a conflict free timetable, train detection and interlocking of routes. ATC allows the automatic control of trains throughout a railway network, obviating the need for train drivers. The Docklands Light Railway in London provides a good example of this type of operation. (Australians use this acronym to describe automatic train protection.)^UoS

Automatic Train Monitoring (ATM)

Subsystem to monitor the train service by means of train describers, track circuit occupation or balise based data collection. ATM is normally a subsystem of automatic train supervision (ATS) and is sometimes also referred to as train service monitoring.^UoS

Automatic Train Operation (ATO)

The subsystem within the automatic train control (ATC) system which performs functions otherwise assigned to the train operator (driver). ATO is not generally considered to be safety critical since interlockings and automatic train protection (ATP) ensure that trains’ routes and movements cannot conflict. Driverless operation of trains requires the transmission of control data using track circuits, inductive loops, balises or radio signals. Radio signals can be diffused by broadcast or leaky cable feeders.^UoS

Automatic Train Protection (ATP)

The subsystem within the overall train control system which automatically ensures compliance with or observation of some or all speed restrictions or movement authorities’. Normally, the term ATP refers to the provision of failsafe protection against collisions, excessive speed, and other hazardous conditions which may arise during train movements by preventing trains from ignoring control commands. This definition covers what could be described as ‘Comprehensive ATP’ (see below). Less effective systems (such as TPWS, AWS and Trainstops) are sometimes also classified as ATP. As a result, the following hierarchy of functionality is proposed, with ATP as the ‘global’ term: Warning Systems ‘systems assisting observation of movement authorities, based upon manual activation’, e.g., the Driver Reminder Appliance (DRA); Automatic Warning Systems ‘systems automatically assisting observation of movement authorities’, e.g. the standard British AWS system; Automatic Train Stop ‘a system automatically enforcing compliance with the limits of movement authorities’; Partial ATP ‘a system automatically enforcing compliance with speed restrictions and movement authorities at some locations or for some vehicles’; Comprehensive ATP ‘a system automatically enforcing compliance with all speed restrictions and movement authorities (for all vehicles) within a given area’. This type of system is often divided into two subcategories, Intermittent ATP and Continuous ATP. There are many different types of implementation but all require the transmission of control data using track circuits, inductive loops, balises or radio signals. Radio signals can be diffused by broadcast or leaky cable feeders.^UoS

Automatic Train Regulation (ATR)

Subsystem to ensure that the train service returns to timetabled operation or to regular, fixed headways, following disruption. ATR subsystems adjust the performance of individual trains to maintain schedules. ATR is normally a subsystem of automatic train supervision (ATS).^UoS

Automatic Train Reporting

Electronic system for reporting train movements based on the passing of train identities using a signal panel train describer.^RT+UoS

Automatic Train Stop

A wayside system that works in conjunction with equipment installed on the vehicle to apply the brakes at designated speed restrictions, block signals or on a dispatcher’s signal, should the driver not respond. Once actuated, the brakes are applied until the train has been brought to stop. See Train Stop.^UoS

Automatic Train Supervision (ATS)

The toplevel system in real time train control which regulates performance levels, monitors the trains in service and which provides data to controllers to adjust the service to minimise the inconvenience otherwise caused by irregularities. The ATS subsystem also typically includes automatic train regulation functions which are implemented through an automatic routing system (ARS). ATS requires automatic train monitoring (ATM) and service monitoring to be able to adjust the timings of trains appropriately. ATS supports automatic train control by managing the routes or network.^UoS

Automatic Vehicle Identification

Semiautomatic mechanism for reporting of train movements based on the location of freight rolling stock and subsequent translation to actual train identities/activities reported to TOPS (generally limited to electricity coal services).^RT

Automatic Vehicle Identification (AVI)

Transponder based system to identify the number and other useful information of any vehicle in a train using a trackside interrogating unit. The passive UIC standard system is lowcost (about US$40 per unit for the hardware). AVI components are also being used for lowcost ATP applications. ^UoS

Automatic Warning System

Used to give advance warning to drivers of a signal aspect, a temporary speed restriction or a permanent speed restriction at least 30% slower than the previous limit.^RT

Automatic Warning System (AWS)

British system for alerting the driver to a signal aspect which requires action (horn for danger) or indicating a clear signal ahead (bell for green). Based on a trackmounted permanent magnet with an electromagnet to cancel the warning.^UoS

Autonomous Traction

A form of traction where the power source is contained wholly on the vehicle (Diesel, gas turbines, battery, flywheel, coal, wood) allowing the vehicle to travel a design range between refuelling. ^UoS

Auxiliary Wayside System

A backup or secondary train control system, capable of providing full or partial automatic train protection for trains not equipped with train borne CBTC equipment, and/or trains with partially or totally inoperative train borne CBTC equipment. The auxiliary wayside system generally includes train borne equipment and may also provide broken rail detection.^UoS

Auxiliary Wire

See Compound Catenary.^UoS

Availability

The ratio between the time during which a piece of equipment (or a human being) is available for operation (whether or not being used) and the total period during which it is needed. Scheduled maintenance, for example, reduces the availability of rolling stock unless carried out during nonservice hours.^UoS

Axle

The part of a wheelset which links the two wheels. Normally, wheels are pressed onto shoulders machined onto the axle. Axles normally have outside bearings which sit in axleboxes. Inside bearings are more difficult to install and maintain but reduce the unsprung mass acting on the track.^UoS

Axle Arrangement

The way in which powered and nonpowered axles are arranged under a vehicle. The most commonly used description distinguishes between powered and nonpowered axles where the letter "A" stands for a single powered axle, "B" for two, etc. while numbers stand for the nonpowered axles:

A1AA1A is the axle arrangement of a locomotive with two bogies, each of which has two powered axles with an nonpowered axle in between;

C0C0 or CoCo is the axle arrangement of a locomotive with two bogies with three powered axles.

Other wellknown arrangements are B0B0B0 (BoBoBo) for heavy locomotives and 1AA1 for EMU cars.^UoS

Axle Counter

Track mounted equipment which counts the number of axles entering and leaving a track section at each extremity; a calculation is performed to determine whether the track is occupied or clear.^RT

B...

Back Drive

Mechanical arrangement to provide an actuation force away from the tip of a set of points, used to ensure that the switchblades are correctly positioned throughout their length.^UoS

Balancing Segment

An accounting function defined so that the general ledger will not allow unbalanced journal entries to be posted. For example, if your business unit segment is a balancing segment, general ledger ensures that, within every journal entry, the total debits to unit 01 equal the total credits to unit 01. ^RT

Balise

Track mounted device for communicating with passing trains. Most are mounted on a sleeper in the middle of the track (4 foot). We distinguish inductive and radio based balises, active and passive balises and intelligent and dumb balises. All balises transmit or transmit and receive information in the form of telegrams, e.g., one of the ERTMS standards allows the transmission of up to 512 bits of information three times while a train is passing at up to 250km/h.

inductive balises operate at low frequencies and use inductive coupling between a fixed coil (antenna) and a moving coil on board the vehicle;

radio based balises operate at several hundred MHz and use aerials embedded in the balise and suspended underneath the front end of the vehicle;

passive balises must be powered up by the passing train, usually using a 100kHz signal coupled inductively. The balise detects the presence of a train and automatically transmits the stored data. This is the most common type of balise;

active balises use an external supply to transmit data and are often used to power track loops (EUROLOOP) where data is transmitted continuously;

dumb balises simply transmit fixed information such as the balise number, number and position of the next balise(s), gradients and speed restrictions etc.;

intelligent balises transmit a combination of fixed and variable information such as the aspects of signals associated with the balise. In some cases they can also receive and process information from the train.

It is possible to have most combinations of the types, e.g., active intelligent inductive balises.^UoS

Ballast

Selected material placed on the sub grade (US: roadbed) to support and hold the track with respect to its alignment within the bounds of specified top (vertical) and line (horizontal). Ballast preferably consists of accurately graded hard particles, normally stone, easily handled in tamping, which distribute the load, provide elasticity, drain well and resist plant growth. Generally, ballast must consist of broken stones. Granite is a very suitable material thanks to its toughness.^UoS

Ballast

The graded stone used for drainage and support of the track. The advantage over slabtrack is that it is easy to move for maintenance work.^RT

Ballast Cleaning

The process of separating dirt (fines and crushed ballast) from the ballast by shaking followed by grading of the stone and by depositing the stone which is still usable back onto the track.^UoS

Ballast Cleaning

The removal of existing ballast using a machine which grades the excavated ballast, returns good stone to the track and takes fine stone and spoil for disposal.^RT

Ballast Mat

A 50 to 70mm thick elastomer mat placed under the normal track ballast on top of a rigid slab or on top of the sub grade to absorb vibration and to assist drainage. Normally, the ballast mat is placed on an intermediate layer of sand.^UoS

Ballast Section

The cross section of a track around and under the sleepers (crossties) and between and above the toes of the ballast slopes. This section may include subballast.^UoS

Ballast Shoulder

The portion of ballast between the end of the sleeper (tie) and the toe of the ballast slope. It distributes the traffic load over a greater width of sub grade and helps hold the track in lateral alignment.^UoS

Ballast Tamper

A power operated machine for compacting ballast under sleepers (crossties) using strong tynes which are pushed into the ballast on either side of the sleeper.^UoS

Ballast Tamping

Compacting ballast under the sleepers to maintain the line and top (US: surface) of track.^UoS

Banner Repeater

A signal whose function is to repeat the indication shown by another signal when the driver cannot see the latter.^RT

Barrow Crossing

A level crossing at the end of a station platform for use by (or under the supervision of) rail staff only.^RT

Base Station Controller (BSC)

Electronic unit controlling the transmissions from several radio antennas in a radio block system.^UoS

Baseplate

A metal casting which supports and holds a flat bottom rail on a sleeper.^RT

Batter

(1) Deformation of the surface of the railhead due to wheel impact (P1 and P2 forces), usually close to the joints (ends of rails) or (2) Receding (sloped) wall as encountered in cuttings and on ledges.^UoS

Bay Line

A dead end line adjacent to a platform.^RT

Bearer

Timber (or concrete) transverse sleeper supporting the rails in switch and crossings. ^RT

Bearing Platform

The top surface of an abutment or pier upon which the superstructure span is placed and supported. For an abutment it is the surface forming the support for the superstructure and from which the hackwall (US) rises. For a pier it is the entire top surface. (US: Bridge Seat.)^UoS

Bell Crank

L-shaped casting or fabrication pivoted in the centre to change the direction of an actuation force (usually used in switch drives, e.g., to create a backdrive.)^UoS

Berth

Name occasionally used for a track circuit.^RT

Berth Offset

The difference between the time a train actually occupies a track circuit and the time recorded in TRUST for the event.^RT

BiDirectional Lines

Rail Lines which are fully signalled to take trains in both directions.^RT

BiDirectional Signalling

Allows trains to run in either direction over the same section of track under the control of an interlocking (builtin safety system) which prevents collisions. Bidirectional signalling is very useful in releasing for maintenance a single track of a twotrack railway but it is more complex and expensive to install than single direction signalling. Singletrack lines always have bidirectional signalling. (Swiss Term: banalised track.)^UoS

Blanketing

A layer under the ballast to stop clay and soil seeping through.^RT

Blast Cleaning

The preparation of a surface by impingement of a stream of abrasive of high kinetic energy particles ("shot"). ^RT+UoS

Block (Section)

A length of track of defined limits onto which one train only is usually allowed at any one time (exceptions include the joining of trains, split platforms and breakdown recovery). The access to and use of the block section is governed by verbal instruction, track warrant, token or track circuit controlled block (section) signals or by some other type of signalling. Older type block signalling requires the presence of block instruments to communicate with adjoining signal boxes.^UoS

Block Bells

These provide a unique manual system of communication between signal boxes. Using an electric single stroke tapper, messages can be passed between boxes in the form of bell codes.^RT

Block Controls

Enhancements to the basic block instruments used in an Absolute Block area. ^RT

Block Indicator

Electrical system which allows communication between two adjacent block posts and which indicates the state of the line between the signal boxes. The system uses a simple twowire link and relies on bellcodes in Britain and polarities in the link between the posts elsewhere.^UoS

Block Instrument (see Block Indicator)

Block Section The section of line between the section signal of one signal box and the Home signal of the next signal box ahead.^RT

Block Signal

A fixed signal at the entrance to a block section, to govern trains and light running locomotives entering and using the block.^UoS

Block Station

A place at which block signals are located and from where they may be operated.^UoS

Block System

Maintains an interval of space between trains (see also Absolute Block).^RT

Block System, Automatic

A series of consecutive blocks governed by automatic block signals actuated by a train or engine or by certain conditions affecting the use of the block.^UoS

Blyth & Tyne

The freightonly route to the east of the ECML between Newcastle and Morpeth, originally built by the Blyth & Tyne Railway Company.^RT

Board

Slang for a signal.^RT

Bobby

Traditional slang for a signalman (The original signalmen were actually Railway Police Officers.)^RT

Bogie (UK)

A four or sixwheeled frame, normally used in pairs under longbodied railway vehicles and on locomotives or individually inbetween two sections of an articulated vehicle. The bogie has a central pivot point, which allows it to turn as the track curves and it thus guides the vehicle into the curve. The pivot point can be real or it can be created by links and flexibility in the suspension. There are almost as many bogie designs as there are bogies. Allwelded boxframe bogies with some steering capability are currently the fashion in Europe. Good design is crucial to achieve a good ride quality, although track condition is also very important in assuring this. See also Articulation. (US: Truck.)^UoS

Bolted Rail Crossing

A rail crossing or "frog" assembled from mill rolled and machined rail of bolted construction, as distinguished from solid cast crossing frogs.^UoS

Bond

Cable or braid used to create the same electrical potential in two places, e.g. to link a signal mast to the rail (earthbond) or a part of the electrification system to another part. Red bonds are used on 25kV electrifycation. (See also Impedance Bond.)^UoS

Bond

A financial transaction where the contractor deposits a defined sum of money with a third party (usually a bank) that is held in bond until the defined tasks have been satisfactorily completed.^RT

Bonding

The technique or action of creating the same electrical potential in two different places.^UoS

Bowmac

A Concrete Panel Which Forms Part Of The Road Surface Over The Track At A Level Crossing. ^RT

Boxing (US)

See Hunting (UK).^UoS

Brace, Rail

A device used points (switches or turnouts), movable crossings (frogs) etc., in combination with point bearer plates, for ensuring the correct distance between rails. Also used on rails in sharp curves to maintain the gauge & prevent overturning of the rail.^UoS

Braking Distance

The distance a train needs in which to stop (or to reduce speed) from travelling at a given speed.^RT

Branch (Line)

Track carrying trains from the mainline to destinations on lower priority routes than the mainline.^UoS

Bridge Assessment File

The file containing or referring to all relevant records resulting from the assessments carried out on a bridge.^RT

Bridge, Ballast Deck

A bridge with a solid floor provided with drains and covered with ballast, to provide normal and uniform support for track which conforms generally to the standard construction used for the tracks where they are constructed on sub grade (roadbed). Requires more height than a bridge with slabtrack or where the sleepers rest directly on the structure.^UoS

Bridge Bash

(see Bridge Strike).^UoS

Bridge, Ibeam

A stringer type bridge in which the stringers are steel Ibeams that directly support the track or ballast section.^UoS

Bridge Strike

A generic term to describe an incident where a road vehicle has hit the overhead structure of a rail bridge. This is a common reason for train delays as the line often cannot be reopened until the bridge is inspected by a suitablyqualified railway employee.^RT

Bridge Strike Nominee

A person who has been certified as competent to implement the procedures for reopening lines at 5 mph, as contained in the Rule Book Appendix ‘Bridges Struck by Road Vehicles’.^RT

Bridge, Through Span

A bridge in which the track is carried between girders or trusses. Girder and pony truss (US) bridges (trusses without overhead braces) are called halfthrough spans; truss bridges with overhead bracing are called through spans.^UoS

Bridge Tie (US)

A sawed sleeper or tie usually preframed and of the size and length required for track on a bridge, directly resting on the structure of the bridge. Usually made from hardwood.^UoS

Britdoc

Name of the company which runs a mailing system using the DX (document exchange) network. ^RT

British Rail Incident Monitoring System

Computer database which provides statistical information on accidents and safetyrelated incidents.^RT

British Rail International

The former arm of BR responsible for running overseas offices and selling tickets to continental destinations. Now trading under SNCF ownership as Rail Europe.^RT

British Rail Staff Association

A national association for the benefit of all members^RT

British Standard

A standard published by the British Standards Institution. Its alphanumeric identity is prefixed by BS. Most British Standards are being superseded by ISO standards. ^RT+UoS

Broad Gauge

Line a track wider than the standard gauge of 4 ft 8½ in (1435mm).^UoS

Bruff

A company which built a type of vehicle capable of running on both road and rail; normally used to travel by road to aid a derailed rail vehicle or to travel to the nearest road access for a remote work site.^RT

Buckle

Failure of a rail by an inelastic change in alignment (usually as a result of compression due to elevated temperature). To lose line of track by bulging.^UoS

Bull Head Rail

An obsolete UK rail profile still in wide use whose top and bottom profiles are mirror images of each other. The rail is symmetrical with respect to the web centreline and is theoretically reversible to extend its life. The designer’s intention was that one could transpose the rails between right and left and then turn them upside down for a further two uses. Corrosion and stresses in the effective foot make this reversal impossible. See also Rail and Flat Bottom Rail.^UoS+RT

Bump Stop

Hard rubber suspension component which stops a movement close to the end of the spring travel of a lateral or vertical suspension.^UoS

Business Management Information System

A suite of custom and offtheshelf software being developed to manage Railtrack finance, procurement and project management, formerly known as FBMIS or FBIS.^RT

Business Risk Assessment

An assessment of the (nonsafety) business risks implicit in a change proposal and associated investment plans.^RT

Business Route Selection

commerciallybased unit of route measurement which enables costs and income to be measured for defined sections of route, based on volume and type of customer usage.^RT

Butt Weld

A weld joining two abutting surfaces by depositing weld metal within an intervening space or by melting both rail ends and then pushing them together. This weld serves to unite the abutting surfaces of the elements of a member or to join members by their elements abutting upon or against each other. Butt rail welding of one rail to another can be accomplished inplant or on site by electric resistance fusion (Flash Butt Welding) or by an aluminothermic process in the field. ^UoS

C...

C Change

A major business initiative launched in June 1996 to rationalise, clarify and standardise Railtrack processes and procedures. The primary focus was to make significant improvements in customer service and control of key activities. ^RT

Cab

The space in the power unit or driving unit of the train containing the operating controls and providing shelter and seats for the driver or engine crew.

Cab Signal

A signal installed in the driving cab of the train repeating or in lieu of lineside signals.^RT

Cadbury Code

Defines the accountabilities of the board, chairman, and nonexecutive directors of a company, in respect of corporate governance, internal control and financial reporting.^RT

Cant

The term used to denote the raising of the outer rail with respect to the inner rail on curved track to allow higher speeds than if the two rails were level. Cant assists in creating the force necessary to accelerate the train laterally to traverse a curve. If a track was canted to the level required to generate the full curving force (equilibrium cant) for the maximum speed of the fastest train, a slower train could topple over. A compromise value of cant is therefore used, leading to ‘cant deficiency’ at higher speeds. Cant is what stops your coffee spilling when you go round a curve (US and Continent: SuperElevation).^UoS+RT

Cant Deficiency

The theoretical amount by which the outer rail would need to be raised to reinstate equilibrium for a train travelling through a curve faster than the equilibrium speed. The existence of cant deficiency will result in pushing your coffee to the outside of your cup.^RT+UoS

Cant Excess

For a train travelling slower than the equilibrium speed on a curve, the theoretical dimension by which the outer rail would need to be lowered to reinstate equilibrium.^RT

Cant Rail

The part of a vehicle or traction unit at which the profile between the bodyside and roof changes.RT

Cantilever

A type of overhead line support, consisting of a mast to one side of the track with supports for contact wire and catenary wire.^RT+UoS

Capex

Capital expenditure (see also OPEX). Funds spent on fixed assets (e.g., the Heathrow Express infrastructure) which are not charged against company profit.^RT

Capital Project

A project resulting in the production of a physical asset for a company.^RT

Car (UK)

Only exists in combination, e.g., railcar. (US: any nonpowered rail vehicle). Car, Hand a four wheeled, hand operated works vehicle for transporting staff and tools. (UK: Trolley)^UoS

Car, Motor

A motordriven works or inspection vehicle. (UK: Powered Trolley).^UoS

Carriage (UK)

Passenger carrying rail vehicle, also referred to as Coaching Stock. (US: Coach)^UoS

Carriage Line

A line used to move empty rolling stock / carriages only.^RT

Carrier Drain

An impervious drain designed to carry water from place to place instead of collecting water from the surface or surrounding soil directly.^RT

Catastrophic Risks

Events with a potential for multiple casualties.^RT

Catch Point

Point leading to a very short dead end or simply used to derail rolling stock attempting an unauthorised movement.^UoS

Catch Points

A pair of sprung trailing points usually located in gradients steeper than 1 in 260. Their purpose is to derail any train running back without authority or out of control. These were a requirement before all vehicles had automatic brakes. Now they are being progressively removed. Sometimes they are worked from a signal box rather than being spring operated.^RT

Catenary

(1) The catenary wire or cable (also known as the messenger wire) carries the contact wire by means of dropper wires. The term was chosen because the catenary wire assumes more or less the shape of the curve adopted by a suspended chain or wire. (2) Generic term used for a power supply arrangement incorporating at least a contact wire and a catenary wire connected by droppers. See Overhead Line.^UoS

Catenary System

Generalised term used to describe the whole overhead line equipment^UoS.

Cat’s Eyes

Slang term for a position light shunting or subsidiary signal.RT

Cattle Guard (grid)

A rail high panel of material difficult for hoofed animals to traverse, used to continue a stock fence across a railway line. See Stock Guard.^UoS

Central Door Locking

A secondary locking system retrofitted to certain slam door trains and controlled by the guard which prevents passengers from opening the doors while the train is moving.^RT

Centralised Traffic Control (CTC)

Remotely controlled system of signals and points under which train movements are authorised by station and block signals whose indications determine the precedence of trains. The manipulation of automatic and/or cab signals and poweroperated turnouts is effected from a central location where indications on panels or displays indicate the position of trains and the state of signals and points. (UK: Power Box or Integrated Electronic Control Centre IECC)^UoS

Centre Siding

A length of track laid between two running lines for the purpose of reversing trains, usually beyond a station. It allows a train to reverse direction without crossing a track carrying through trains. Sometimes referred to as a "reversing siding". (US: pocket track or turnback track). ^UoS

Certificate of Acceptance

A certificate that is issued in accordance with GO/RT/3270 Route Acceptance, which requires a Certificate of Conformance to be issued for the locomotive design, construction, testing, examination and maintenance.^RT

Certificate of Authority to Operate

A formal certificate signed and issued by the RSAB documenting the conditions under which a T&RS Route Acceptance Request has been accepted. This certificate specifies the equipment, the equipment configuration, operational requirements and limitations, route constraints and network factors within which approval has been granted for network operations.^RT

Certificate of Technical Acceptance

The formal signed certificate issued by the RSAB confirming that a technical design proposal conforms to Network Rail technical standards for route acceptance and represents a suitable basis for development for network applications. This certificate specifies the equipment, the equipment configuration, limitations, route constraints and network factors within which approval has been granted.^RT

Cess (UK)

The area either side of the railway immediately off the ballast shoulder. This usually provides a safe area for authorised workers to stand when trains approach.^{RT+ UoS}

Chain (UK)

Unit of length common on UK railways (80 chains to a mile, 22 yards per chain and 1 chain = 66 feet.)^{RT+ UoS}

Chair

The cast steel fixture on a sleeper, which secures rail (particularly bullhead rail) in the correct position. Depending on the design, of which there are many, the rail is secured to the chair by a form of clip, key or spike. ^UoS

Chargehand (or Chargeman)

An obsolete job title for a train operator or infrastructure owner employee who has a supervisory role on a station platform.^RT

Check Rail

(1) A rail laid parallel to and inside a running rail to prevent wheels from being derailed or to hold wheels in their proper alignment while crossing the stock rail. Check rails prevent wheels from striking the blades of points and the tips of crossings.
(2) An additional pair of rails laid parallel to and between the running rails on bridges, bridge approaches, and in other critical locations, to keep derailed wheels on the sleepers and near the running rails. (US: Guard Rail.)^UoS

Check Rail Clamp

A device consisting of a yoke and fastening devices fixing the relative positions of the running rail and guard rail. Not all checkrails have clamps.^UoS

Chisel, track

A handheld tool to be struck by a sledge hammer, for cutting rail by scoring the base and web until breakage occurs, or for similar cutting. A rail cutter.^UoS

Circuit, Track

See Track Circuit^UoS

Claims Allocation and Handling Agreement

An agreement between railway operators which empowers Railway Claims Ltd to act on behalf of the industry and its contractors for an accident or incident where a third party claim affects a number of organisations.^RT

Clamp

A device used to secure the closed switch of a pair of points to the stock rail. Sometimes known as a clip.^RT

Clamp Lock, or Clamplock

A point operating mechanism which locks the points by directly clamping the closed switch rail to the stock rail. Normally operated hydraulically.^RT+UoS

Clamp Lock Heater

A cartridge type heater fitted to a clamp lock mechanism operating the points blades.^RT

Class of Train

Class 0 Light locomotive (locomotive running on its own; Class 1 Express passenger trains, mail trains and some emergency trains; Class 2 Stopping passenger trains; Class 3 Express parcel trains; Class 4 Express freight trains 75mph maximum speed; Class 5 Empty coaching stock trains (passenger vehicles running empty); Class 6 Express freight trains 60mph maximum speed; Class 7 Freight trains with 45mph maximum speed; Class 8 Freight trains with 35mph maximum speed; Class 9 Eurostar trains. ^{RT +
UoS}

Clearing House Accounts Payable

A system for financial settlements between Network Rail and between TOCs.^RT

Clip

Often called a "clamp", that is used to secure the closed switch of a pair of points to the stock rail, to prevent unauthorised or unintentional movement of the points.^RT

Clip, Switch

The device by which the switch rod is joined to the switch rail. It is usually united with the switch rail by bolts or rivets. It sometimes has staggered bolt holes or similar devices in the horizontal leg for making detailed adjustments in the positions of the switch rails.^UoS

Clip, Transit (switch)

A switch rod clip drilled with several holes in a line diagonal to the axis of the switch rod, for effecting adjustments in the throw of the switch.^UoS

Clockface Timetable

A timetable where trains run at regular intervals (e.g., every 10 minutes.)^RT

Closed Circuit Television

Often used for station security and monitoring level crossings.^RT

Closure Rail (US)

The lead rails connecting the heels of a switch with the toe ends of a frog. ^UoS

Coach

A type of railway carriage, usually with a centre aisle and two rows of seats.^UoS

Coasting

Allowing a train to freewheel (on the flat or downhill) to minimise energy use. Of the 50 non stop electrified miles between London and Brighton, 29 miles can be run with the train coasting. ^UoS

Coasting Allowance

Additional time in a schedule to allow trains to coast part of the journey.^UoS

Code of Practice

A statement of best practice whose use is not made mandatory by the issuing authority.^RT

Collector Drain

See surface water drain.^RT

Communications Based Train Control (CBTC)

A continuous automatic train control system characterised by: (i) high resolution train location measurement, independent of track circuits; (ii) continuous, high capacity, bidirectional traintotrack RF data communications; and (iii) trainborne and wayside vital processors capable of implementing vital functions. In the UK it is known as Transmission Based Signalling (TBS). In Europe it is ETRMS Level 3. ^UoS

Communications Engineer

An engineer, acting for or on behalf of Network Rail, who is competent in railway communications and who is appointed in accordance with section 2 of RT/E/P/30022.^RT

Compound Catenary

An overhead line arrangement which includes a catenary wire, auxiliary wire and contact wirelinked by droppers. All three wires share the traction element (UK MK 1OLE).^UoS

Compromise Bars (US)

Specially machined rails to connect rails of different section in such a way that the gauge sides and the top of the head and running surfaces are held in line. Also called offset bars.^UoS

Condition of Track

This is a reason for a restriction below normal speed which ensures that trains pass at a safe speed over a track or a bridge or an embankment which is not currently fit for line speed.^RT

Conductor Rail

An additional rail (or rails) provided on those electric railways where power is transmitted to trains from the track. Often referred to as the 'third rail' or 'current rail', it is normally at positive potential and is mounted on insulators to the outside of and slightly higher than the running rails. The return of the circuit is via the running rails. The current is collected by the train through 'shoes', attached to the bogies, which slide on top, along or under the rail. The continuity of conductor rails must be broken at junctions in the track to allow continuity of the running rails. Such 'gaps' may cause momentary loss of power to the train. There are cases from time to time of trains becoming 'gapped' at complex junctions, i.e. they stall over a gap and have to be rescued by another train. London Underground has a fourth rail (negative) for a completely insulated circuit. This is known as a fourrail system and the running rails are at an offset potential between the contact rails. Modern 3rd rail systems are under – pinning to allow the installation of protective (insulating) covers.^UoS

Confederation of British Industry

Network Rail is a corporate member, therefore any designated manager is eligible to attend members’ meetings.^RT

Conicity

The taper profiled onto the surface of a railway wheel that assists guidance around curves. Usually 1:20 or 1:20 with part at 1:40.^UoS

Consist

Train formation, e.g., 'This vehicle was in the ’consist'. The sum of all vehicles in a train (for all train types). ^UoS

Construction Work

Maintenance, renewal, new work and commissioning in relation to the following:

civil engineering, signalling, electrification, telecommunications, plant and electrical distribution and related computer systems;
demolition and dismantling operations;
waste removal resulting from demolition or dismantling.^RT

Contact Patch

The contact area between the wheel and the rail. Normally said to be about 1cm² in size and experiencing very high pressures. See also rolling contact fatigue.^UoS

Contact (Trolley) Wire

The overhead wire, sometimes referred to as trolley wire, which the pantograph of an electric locomotive, rides against (contacts) to collect its electrical current (source of power) and which is carried by the catenary or messenger wire.^UoS

Contact Wire

Harddrawn copper, silver or (in Russia) aluminium wire, which is normally suspended from a catenary wire by droppers and is swept by the stainless steel contact strip (Japan) or aluminium contact piece (France DC electrified lines) of the pantograph.^UoS

Contact Wire

The overhead wire touched by an electric train’s pantograph in order to draw power.RT

Contenary

Special type of overhead wire used where clearances are tight. The term is a contraction of ‘contact’ wire and ‘catenary’. ^RT

Continuous Welded Rail

Comprises rails welded together to form a single rail length over 36m (120ft), or 55m (180ft) in tunnels with a limited temperature range.^RT

Continuously Welded Rail

A number of lengths of rail welded together to stretches of 300m or longer in a factory or permanent way yard and then welded together in a seamless manner. Expansion joints are fitted to prevent buckling.^UoS

Contract Approval Group

A committee, chaired by the Head of Procurement, that reviews and approves proposed contract strategies, and contract awards over £5m.^RT

Contract Check

An activity which assesses the extent to which a contractor’s work, procedures or systems meet his contractual obligations. This includes systems, technical and safety checks, and inspections of the contractor’s activities^RT

Contract Check Plan

A plan indicating activities, timescales and Network Rail sections responsible for undertaking individual verification of elements of all maintenance contract work coordinated and managed by the Senior Contracts Manager.^RT

Contract Instruction

An instruction by the Employer to the Contractor relating to an activity which is included in the terms of the contract and which does not vary the contract.^RT

Contract Strategy

The precise way in which an individual contract is organised, planned, and implemented. It will include a timetable for preparation, invitation to tender, and award of contract, with the necessary approval stages involved. It will also include key criteria for the conditions of contract, the approach to the market, the way in which available competition will be exploited, and the tender evaluation criteria.^RT

Contract Strategy Report

A report prepared by the Procurement Manager in advance of an invitation to tender to define the strategic approach when entering the supply market and the proposed structure of the intended contract.^RT

Contractor

A generic term used to describe a company, consultant, partnership or individual supplying works, goods or services to Network Rail.^RT

Contractor Check Plan

The infrastructure maintenance contractor’s plan for internal checking of their end product^RT

Contractor’s Assurance Case

A document specific to a particular maintenance or renewals contract in which a contractor sets out to demonstrate his intention, competence, capability, organisation, risk assessment, and safety management system to undertake the contract work or service requirements in a safe manner, formerly known as Contractors Railway Safety Case.^RT+UoS

Contractor’s Core Safety Case

A set of documents specified by and provided by the contractor to demonstrate that he has the resources, skill, experience and ability to safely carry out all tasks in pursuance of his undertaking. These documents are neither project nor contract specific.^RT

Contractor’s Core Safety Case Review Panel

A panel of no more than four members set up by the Director Line Safety and composed of representatives from both the process and technical functions. Members may be chosen from Zone, Property, Project Delivery and Engineering and Production management units, as well as professional heads, engineers and specialists for resourcing the panel.^RT

Control Centre of the Future

Computerised enhancements to the facilities available in control rooms, an AEA Technology Rail project.^RT

Control Duty Manager

The person in charge of the shift in Network Rail zone control.^RT

Controllable Income and Expenditure

Income and expenditure able to be regulated/controlled by the cost centre budget holder.^RT

Controlled Copy

Copy of an important document whose recipients receive updates whenever the document changes.^UoS

Controlled Document

A document specifying key safety, environmental, procedural or technical aspects of the work of Network Rail staff which must be made available to post holders on a controlled basis in order to allow them to carry out their duties.^RT

Conventional Interoperability Directive

A European Union Directive which requires that national railways technical and operational standards are gradually unified.^UoS

Corrugated Rail

Railhead with regularly spaced ridges and valleys at 90⁰ to the direction of travel which can have a variety of causes, not yet fully explained. ^UoS

Cost Centre

A unique identifier in the set of accounts used to collect the costs relating to the specific activities of a manager within the budget approved.^RT

Crane, track (also called maintenance crane)

A poweroperated crane used principally for positioning rails during track renewal, but having many similar uses in maintenance work.^UoS

Creep Force

The force generated due to creepage.^UoS

Creepage

The ratio of the tangential velocity of the wheel, to the actual velocity of the train.^UoS

Crib

(1) The ballast or the open space between two adjacent crossties.
(2) A crisscross structure of logs, timber, concrete or other members, used to retain a fill or as a bridge support.^UoS

Cripple Line

Siding for failed trains.^RT

Cripple Siding

Track used for storing failed rolling stock.^UoS

Crippled Rail

A rail that has been locally bent by mishandling, derailment or other impact.^RT

Criterion Based Interviewing

A technique used by suitably trained persons to select staff for appointment and posts (often used in conjunction with psychometric tests.)^RT

Critical End Product

An end product that, in consideration of importance ranking and loss contribution, is assigned a value which is above W.^RT

Critical Rail Temperature

The rail temperature to which continuously welded rail may be allowed to heat up before measures to protect traffic must be taken. The CRT will depend on the stressfree temperature of the rail and the quantity and degree of consolidation of the ballast.^RT

Critical Speed

Speed at which hunting continues without dying away. Above this speed hunting increases and derailment can occur.^UoS

Cross Level

Difference in height of the railhead surfaces of the two rails in tangent (straight) track.^UoS

Crossing (UK)

Location in a point (turnout) or diamond crossing where the wheel crosses the rail which is not leading in its direction of travel. This can be cast, fabricated or made using a combination of technologies. Requires a flange way for the wheel flange to pass through. High speed and heavy haul railways use swing nose crossings (moving frogs). (US: Frog)^UoS

Crossing Protection

An arrangement of signs or electric signalling devices designed to prevent accidents at grade crossings. May include short arm gates or full gates.^UoS

Crossing, Grade (Xing)

A crossing or intersection of a railway line and a highway at the same level or grade. (UK term is "level crossing").^UoS

Cross Level

The distance one rail is above or below another. This quality measurement should not be confused with superelevation or cant in curves.^UoS

Crossover

A track providing a connection between two parallel tracks using two turnouts (sets of points. A scissors crossover provides two connections, one in each direction, with a crossing in the middle. In the UK, trailing crossovers are preferred over facing crossovers since they are perceived to be safer. A facing crossover allows a train to change to a parallel track without having to reverse.^UoS

Crossover

Connection between two tracks which allows trains to pass from one to the other.^RT

CrossSpan Wire

A wire stretched across tracks holding the OLE in its desired position.^RT

Cross Tie (US)

The transverse member of the track structure to which the rails are spiked or otherwise fastened to provide proper gauge and to cushion, distribute, and transmit the stresses of traffic through the ballast to the roadbed. Also see Tie (US) or Sleeper (UK).^UoS

Culvert

Small bridge or pipe carrying a stream under a railway or road.^RT

Curve, Compound

A curve composed of two or more simple curves which join on common tangent points or common transition curves and which lead in the same general direction, i.e., to left or right, but each with a different radius.^UoS

Curve, Easement

See: Transition Curve. ^UoS

Curve, Reverse

A curve composed of two simple curves which join at a common tangent point or by a short tangent track or a reverse transition curve, and bear in opposite directions, i.e., to left and right or vice versa. (US: DogLeg)^UoS

Curve, Simple

A curve in the form of an arc of a circle usually described as to its degree of curvature.^UoS

Curve, Vertical

A curve in the profile of a track to connect intersecting grade lines and to permit safe and smooth operation of trains over summits and across sags.^UoS

Curved Lead

The rail from the heel of the point to the toe of the crossing.^UoS

Cut (US)

Uncoupling part of a Train. (UK) referred to the sections into which a train was broken when passing over a hump in a marshalling yard (now obsolete). ^UoS

D...

Dabbing InEnthusiasts’ jargon for trespassing on the network to take photographs of trains.^RT

Datatrak

Semiautomatic mechanism for reporting of train movements based on the location of multipleunit rolling stock and subsequent translation to actual train identities/activities based on the GEMINI vehicle control system.^RT

Deadhead

A locomotive hauling another. In addition, a nonrevenue (nonpassenger) train movement. Deadheading is a US term for empty train or light engine running. The movement of surplus personnel, usually drivers, without them performing their duties.^UoS

Deadman Device

A pressure or activity actuated alertness device to detect inattention or disability of a train driver (operator). ^UoS

Deenergised Apparently Dead

Electric apparatus, such as overhead wires, third rail, transformers, switches, motors, etc., is deenergised when disconnected from the normal power source, but such apparatus is deemed dangerous to life until it is known to be properly grounded.^UoS

Degree of Curvature

A measure of the sharpness of a simple curve in which a 1deg. Curve is taken as the central angle subtended by a chord or arc of 100 feet and for which the radius is taken as 5,730 feet. Railways in the US use the chord definition highways the arc definition.^UoS

Delegated Authority

The authority, usually expressed in financial terms, that an individual post in the organisation has to enter into the specific transaction to which the authority relates.^RT

Delegated Budget Authority

The authority to commit expenditure within approved budgets in running the business.^RT

Delegated Procurement Authority

The authority to act on behalf of the Head of Procurement to commit Network Rail contractually to third party suppliers of works, goods and services.^RT

Deliverer

The management team engaged by the Sponsor to manage the day to day delivery of a project to a scope and purpose consistent with the business case provided by the Sponsor (see Sponsor).^RT

Departmental Advice (Blue)

Used for publishing the Sandite programmes worked by TASC units (see TASC).^RT

Depreciation

The charge reflected in the financial accounts for the use and replacement of fixed assets.^RT+UoS

Depth, Ballast

The depth from the bottom of the sleeper or tie to the top of the subballast or sub grade. The ballast between the ties (in the cribs) is a part of the ballast section but its depth is not a part of the specified ballast depth.^UoS

Derail

A track safety device to guide nonauthorised train movements off the rails at a selected spot, as a means of protection against collisions or other accidents. Modern day equivalent for catchpoints in areas with slow moving traffic. Usually linked to a point giving access to a main line or through track.^UoS

Derailment

Anytime the wheels of a rail vehicle are off the head of the rail and on the ground. Caused by collisions, mechanical failure, gauge spreading or flange climb.^UoS

Detection

Proof that points are correctly set (and usually locked) in the "Normal" or "Reverse" position. Correct detection must be obtained before the protecting signal can be cleared.^RT

Detonator

A small disc shaped warning device, designed to be placed on the railhead for protection and emergency purposes. It explodes when a train passes over, thus alerting the driver. Detonators are being phased out. Correctly known as a fog signal.^RT+UoS

Diagram

The planned movements for a set of rolling stock (e.g., a train, a multiple unit) for a day or any other period and involving several journeys, generally with different service (train) numbers.^UoS

Diamond Crossing

Arrangement of a line where one track crosses another, without connection, at an angle of less than 90º, at grade. Named after the pattern formed by the rails.^UoS

Diesel Multiple Unit (DMU)

See Multiple Unit ^UoS

Differential Global Positioning by Satellite (DGPS)

Navigation based on signals received from four or five satellites with a correction factor received from a fixed position reference transmitter via terrestrial FM.^UoS

Direct Fixation Track

A system to attach rails directly to a solid, nonballasted surface. (UK: Slab Track). ^UoS

Direct Rail Services

Originally, the freight operating organisation of British Nuclear Fuels. Now a medium sized freight operating company, active in coal traffic and infrastructure maintenance supplies.^RT+UoS

Direct Traffic Control(DTC)

System of traffic control with sections of track identified with clear boundaries, where permission to proceed is granted remotely by a dispatcher. Ordinarily, only one train may occupy a DTC block at a time. Similar to train warrant control (TWC) except that the section entry timings are fixed by timetable rather than granted case by case. DTC may be used in conjunction with track signalling in APB, ABS, or over "dark territory". ^UoS

Disability Discrimination Act (DDA)

Legislation requiring providers of services that are made available to the general public take into account the needs of people with disabilities. Part 3 of the Disability Discrimination Act (DDA) came into force on 1^st October 2004 and requires every business, large or small, from the local shop to restaurants, health clubs, dentists and supermarkets, to become more userfriendly for Britain’s 10 million disabled people. The law means that businesses will need to make reasonable changes, such as adapting premises, removing physical barriers or providing the service another way, so that disabled people can use the service. Failure to act can result in legal action. This legal requirement has been anticipated by the railway industry and has caused substantial cost increases. ^UoS

Disaggregation

The splitting of plans and expenditure into different headings and activities.^RT+UoS

Displaced Asset

An asset owned but no longer in use.^RT

Distant Signal (AU, CH, D etc.)

Hixed signal which indicates the state of the main signal on the approach to a block signal, station entry or exit signal etc. It will not convey information as to conditions affecting the use of the track between the distant signal and main signal. Distant signals are necessary where a train driver can not react fast enough once he or she sees the main signal. Often combined with the previous main signal.^UoS

Distant Signal (UK)

Fixed signal outside of a block system, used to indicate the state of the main signal on the approach to a block signal, interlocking signal or switch point indicator. It does not convey information as to conditions affecting the use of the track between the distant signal and block signal, interlocking signal or switch point indicator with which it is associated. The distant signal does therefore not include a red or stop aspect. When "on" it is a warning that the next aspect could be red. Distant signals are necessary where a train driver cannot react fast enough once he or she sees the main signal. It is identified by a "D" marker (UK). ^{UoS+ RT}

Division Point (US)

One of a number of sections of a large railway, run as an independent entity to the extent of having its own fleet of locomotives, engines, repair shops, officials, and clerical and operating personnel. Sometimes only refers to the management of part of the infrastructure. (UK: Area)^UoS

Document Control Point

A nominated location where the person in charge will receive controlled documents, allocate controlled copy numbers, register them, acknowledge receipt and pass them to each addressee. The person in charge will also register outgoing documents, and ensure receipts are received from each addressee.^RT

Dog Leg (US)

Railway parlance for a sharp reverse curve in the track. The term's basis is the comparable crooked appearance of a dog's hind legs. (UK: reverse curve)^UoS

Dolly

Slang term for a shunting signal in ex LNER terminology. Sometimes also known as a "Dod" or "Tommy Dodd". ^Rt

Dolly, Rail or Timber (US)

A device consisting of one or more wide rollers mounted in a frame, used as a platform and as a truck for moving rail, long heavy timbers, and other items. (UK: Trolley)^UoS

Double End Electrical Section

A section of conductor rail or overhead line fed from two points.^UoS

Double Yellow Aspect

A preliminary cautionary signal in four aspect signalled teritory, informing the driver to expect the next running signal to be at single yellow.^RT

DoubleEnder (US)

A locomotive able to run in either direction. Most European locomotives are of this type , unlike US ones which often run in back to back pairs.^UoS

Down Line

Rail line taking trains away from London or another major city (generally). However, there are exceptions, for example, Up to Cleethorpes and Up to Hull from Seamer West.^RT

Drill, Track

A machine designed to operate horizontally to drill holes through the webs of rails, especially for track bolts. It may be a oneman ratchet drill or a geared drill machine with a frame, rail clamps, feed screw, highspeed steel bit and chuck.^UoS

Driver’s Safety Device

Device on traction rolling stock that will stop the train if the driver becomes incapacitated. Popularly known as the "Deadmans Pedal" or Deadman’s Handle".^RT

Driving Van Trailer

An unpowered van fitted with a driving cab from which a locomotive at the other end of the train can be controlled, thus enabling pushpull working.^RT

Dropper

Stainless steel or galvanised steel wire supporting the contact wire from the < size="2">catenary wire < size="2">and linking the two electrically. Fixed to the contact wire with clips.^UoS

Dual Gate

Electronic means of monitoring two selected regions of the timebase of an ultrasonic flaw detector.^RT

Dual Voltage Locomotive (Train)

Locomotive or multiple unit train designed to operate over lines having two different electric traction power supply systems. Locomotives have been designed to operate with up to four different voltages covering both AC and DC systems. Some trains can operate on lines with either overhead or third rail current collection, as in the case of Eurostar Trains and UK Class 92 Channel Tunnel locomotives and some North East Corridor trains in New York. Eurostar trains can handle 750Vdc (England) 1500Vdc (Holland + France), 3000Vdc (Belgium) and 25kVac (Belgium and France).^UoS

Dummy

Slang term for a shunting signal, ex LMS terminology.^RT

Dwell Time

The time a vehicle or train spends at a station or stop to allow passengers to board and alight, measured as the interval between time of stopping and starting.^UoS

Dynamic Braking

A train braking system using the traction motors of the power vehicle(s) to act as generators with the energy dissipated in brake resistors (rheostatic braking) or supplied to other trains via the supply system (regenerative braking).^UoS

Dynamic Track Stabiliser

A self propelled ontrack machine for consolidating track ballast by inducing high frequency vibration into the ballast through the rails and sleepers. This treatment allows resumption of operations at line speed after a maintenance intervention (tamping etc.).^RT+UoS

E...

Early Rationalisation of Signalling Railtrack’s accelerated programme of closing small signal boxes and concentrating work at fewer, larger signal boxes.^RT

Easement Curve

See Transition Curve.)^UoS

Economical Facing Point Lock

A mechanism that enables the movement of points and the facing point lock plunger to be operated by the same lever.^RT

Egret

A performance management information system with downloaded information from PHIS.^RT

Elastomer

A material made substantially from natural or synthetic rubbers.^RT

Electric Multiple Unit (EMU)

The generic term for an electrically powered suburban or train where a separate locomotive is not required because the traction drive and control system is contained under or in the roof space of various cars in the train (see also multiple unit. ^UoS

Electrical Control Room

Responsible for control of current in the overhead lines. On the LNE zone, located at Hornsey and Doncaster, with Cathcart controlling Alnmouth Berwick.^RT

Electrical Control Room Operator

The person in charge of a shift in the Electrical Control Room.^RT

Electrification

A term used to describe the installation of overhead wire or third (or 4^th) rail power distribution facilities to enable operation of EMU trains or trains hauled by electric locomotives.^UoS

Electrified Territory

That portion of the railway consisting of main tracks, secondary tracks, sidings, yards and industrial tracks equipped for electric train operation by overhead line system or by third rail and necessary substations, transmission and signal power lines located above or adjacent to the tracks.^UoS

Electro Magnetic Interference

Interference in the signalling system caused by inductive coupling with traction motors, transformer stray fields, radio waves being generated by electronic equipment etc.^UoS

Electromagnetic Compatibility

The ability of electronic devices to function satisfactorily in the presence of magnetic and electric fields.^RT

Electronic Data Interchange

A computer network enabling suppliers and customers to pass orders, invoices, and payments electronically.^RT

Electronic Train Recording

Computer equipment installed in signalboxes where automatic TRUST reporting is not operative, to allow the signalman to record train passing times. Now known as Simplified Direct Recording (SDR).^RT

Electronic Train Register Book

Being installed in manual signalboxes to replace the old manual train register. A PC based system.^RT

Elevation (US)

Height of outer rail in a curve: See Superelevation.^UoS

Emergency Restriction of Speed

A reduction of normal speed which has to be applied in an emergency.^RT

Encapsulation

The bonding of insulating material to a metallic fishplate core under workshop conditions prior to the manufacture of a joint.^RT

End Post

Block of insulating material in the shape of the rail crosssection used to separate, electrically, rail ends from each other (also known as ‘biscuit’ in Scotland).^UoS

End post

The piece of an insulating rail joint which separates the rail ends.^UoS

Energised Live (Dangerous to Life)

Electric apparatus, such as overhead wires, third rail, transformers, switches, motors, etc., that is energised when connected to the normal power source. All systems are considered to be energised until a qualified individual establishes that the circuit has been deenergised and has applied a secure link to earth.^UoS

Engine Burn (US)

Destruction of railhead metal caused by spinning locomotive wheels. Engine Burn Fracture is a rail break caused by an engine burn.^UoS

Engineering Safety Management System

The management system that was employed by Railtrack EE&CS to ensure best current safety management practice.^RT

English, Welsh and Scottish Railway Ltd

The company formed when the three heavy haul rail freight companies (Loadhaul, Mainline and Transrail) together with Rail Express Systems, were taken over by Wisconsin Central Railroad Company.^RT+UoS

Environment

Surroundings in which an organisation operates including air, water, land, natural resources, flora, fauna, humans, and their interrelation. Note: surroundings in this context extend from within an organisation to the whole system.^RT

Environmental Impact

Any change to the environment, whether adverse or beneficial, wholly or partly resulting from an organisation’s activities, products or services. ^RT

Environmental Impact Assessment

The ongoing identification of environmental factors to determine the past, current and potential impact (positive or negative) of an organisation’s activities on the environment. This process includes the identification of the potential regulatory, legal and business exposure, as well as health and safety impacts and environmental risk assessment.^RT

Environmental Management System

The part of the overall management system that includes organisational structure, planning activities, responsibilities, practices, procedures, processes and resources for developing, implementing, achieving, reviewing and maintaining the environmental policy.^RT

Environmental Policy

A public statement of the intentions and principles of action of an organisation regarding its environmental aspects, giving rise to its objectives and targets.^RT

Environmental Statement

A document setting out the results of an environmental impact assessment. It consists of three parts:

main study findings;
technical appendices;
nontechnical summary.^RT

Equilibrium Speed

The speed of a train travelling through a curve where the passeger experiences no lateral force, whether to the inside or outside of the curve, the speed at which there is neither cant deficiency nor cant excess. ^RT

Equivalent Fatalities

All fatalities and injuries expressed in terms of fatalities where 10 major injuries equals 1 fatality and 200 minor injuries equals 1 fatality.^RT

Equivalent Million Gross Tons Per Annum

A measure of the damage effect on the track caused by different types of trains running at different speeds and with different axle loads.^RT

EROS

(1) Emergency Restriction of Speed: a reduction of normal speed which has to be applied in an emergency or (2a) Efficiency by the Rationalisation of Signalboxes and (2b) Early Rationalisation of Signalling, Railtrack’s accelerated programme of closing small signal boxes and concentrating work at fewer, larger signal boxes.^RT+UoS

ETH Index

The Electric Train Heating Index states the power which a headend power unit must supply to a railway carriage for "hotelpurposes", that is, heating and air conditioning etc. Also, the capacity of the headend unit to supply this power.^UoS

Ethernet

Computer network system.^RT

Ethylene Vinyl Acetate

A high density polyethylene modified by the addition of vinyl acetate.^RT

European Integrated Railways Radio Enhanced Network (EIRENE)

PanEuropean development project for a train radio system suitable for transmitting the information required by ERTMS. Uses GSM in the 900MHz band allocated to railways.^UoS

European Rail Traffic Management System (ERTMS)

High level set of standards to allow interoperability and effective management of Trans European railway operations. Previously, there was no distinction between the management aspects and the technical solution, European Train Control System (ETCS).^UoS

European Train Control System (ETCS)

The signalling equipment aspect of ERTMS with its three levels of train control. The Level 1 is effectively a standardised ATP system with line side signals. Levels 2 and 3 require output from project EIRENE to assure transmission of movement authority by radio.^UoS

EuroSPIN European Seamless Passenger Information Network

An EC funded project led by W S Atkins to develop an intelligent system which provides uptodate, multimodal passenger transport information to the public.^RT

Examining Engineer

A person who is competent in the examination, assessment and maintenance of bridges to the satisfaction of the Zonal Civil Engineer.^RT

Executive Grade

Old style executive job grading system.^RT

Expansion Joint

A joint provided in CWR to allow rails to expand and contract as the temperature changes without buckling or rail breaks occurring. ^UoS

Expansion Shim (rail)

Spacer inserted between ends of abutting rails while track is being laid to provide allowance for the expansion of the rail steel when the temperature changes.^UoS

F...

Facing Point

Lock a device to ensure that points that allow trains to change route without reversing are locked in position.^RT+UoS

Facing Points

Points where two routes diverge in the direction of travel [compare with trailing points].^RT

Fail Safe

Design philosophy which results in any expected malfunction or failure maintaining or placing the equipment in a safe state.^RT+UoS

Faregate (US)

Part of an automatic fare collection (AFC) system where the device is placed at station entrances and exits to regulate access by reading a ticket inserted by the passenger and restricting access if the ticket is not correct. Various types are in use around the world to prevent passenger fraud and to permit the handling of large numbers of passengers with a minimum of staff. (UK: Ticket Barrier / Ticket Gate)^UoS

Fares Incentive Adjustment Payment

A modification to the fare cap to take into account the punctuality and reliability achieved by the TOC.^RT

Fares Increase Regulatory Mechanism

A computerised system commissioned by OPRAF to check TOC compliance with the fare capping regime. ^RT

Fastener, TiePlate

A special tieplate long enough to support the bases of a guard rail and the adjacent running rail and with a rail brace riveted to it for supporting the guard rail.^UoS

Fastenings, Auxiliary Track Spring

Washers, tie plates, rail braces, rail anchors and other accessories.^UoS

Fastenings, Track

A term commonly applied to splice bars, bolts, clips and spikes.^UoS

Fault Reporting and Monitoring of Equipment System

Allows operators in Fault Control to record Signals & Telecommunications faults.^RT

Feasibility

A structured process that identifies the engineering options and their implications including environmental issues. It culminates in a feasibility report and a design development proposal.^RT

Feasibility Study

A structured process that identifies the engineering options and their implications including environmental issues. It culminates in a feasibility report and a design development (and, sometimes, implementation) proposal.^RT

Feather

Slang term for the row of five white lights mounted at an angle above a (cleared) colour light signal to give an indication of the route set.^RT

Feeder Station

A building or compound containing electrical switch gear and equipment to which main supplies from an electricity company are brought and from which the OLE or third rail is supplied.^RT

Field Reporting Procedures

The instructions issued on how to report to TOPS for any particular location.^RT

Finance and Business Information System

A homonym of FBMIS and which is now known as BMIS.^RT

First Filament Failure

This refers to a failure in a signal lamp, which has more than one filament for enhanced availability. The bulb must be replaced, but the signal still works normally and cautioning of trains is not necessary.^RT

Fish Plate

Device to secure the ends of two rails together (in jointed track).^RT

Fish Plate

Shaped and drilled (4 or more holes) steel plate used to link two rails. Fishplates are bolted to the rail ends by using the space in the web of the rail of jointed track. ^UoS+RT

Fishing Space (US)

Space between head and base of a rail occupied by a splice bar (angle bar, joint bar).^UoS

Fishing Surfaces

Inclined surfaces under the railhead and above the rail foot that allow the fishplate to perform its function of aligning the adjacent pieces of rail.^UoS

Fixed Asset

An item by the use of which the company generates income. This may be a tangible asset or an intangible asset, such as software.^RT

Fixed Distant Signal

A distant signal that is only capable of displaying a caution.^RT

Fixed (Signal)

(1) A signal which is incapable (permanently or temporarily) of being cleared.
(2) A lineside signal which is always there as opposed to a (portable) hand signal.^RT

Flagman (US)

The rear brakeman. The great country music singer Jimmie Rodgers used to brag about being a flagman. Reason? Because flagmen had to know how to read so they could understand train orders.^UoS

Flaking

One of the consequences of rolling contact fatigue, resulting from the propagation of cracks underneath and parallel to the surface of the rail head or running surface of the wheel. The phenomenon is more pronounced on rails where the traffic is predominantly in one direction. Railhead damage takes the form of pieces of the rail or tread surface becoming detached or being torn off. The severity of the damage caused by flaking is generally felt to be less than that associated with shelling and spalling. However, this is a largely qualitative form of differentiation. ^UoS

Flange

Raised part of the rolling surface of the wheel used for guidance in tight curves and when travelling through the crossing parts of turnouts (points) without a moving frog (see also wheelset)^UoS

Flange Way

Space in the crossing of a turnout (points) or diamond crossing that allows the flange of the wheel to cross the stock rail. Space between the running rail and guard rail or the decking (timber or proprietary design) in road crossings to provide clearance for the passage of wheel flanges. ^UoS

Flare Opening (US)

Horizontal distance between the gauge line of the running rail and the side of the head of a guard rail or crossing wing rail at the widest part of its flared end.^UoS

Flat

The railway equivalent to a puncture. Damage caused to the surface of a wheel, normally the result of sliding or skidding; can only be corrected by using a wheel lathe to restore the correct shape.^RT

Flat Bottom Rail

Rail which is used in all modern track relaying.^RT

Flexibility Premium

A percentage allowance paid to Relief Signalmen and Crossing Keepers to compensate for their travelling to and from places of work and the unpredictability of shifts.^RT

Floating Slab Track

A track system using a concrete base mounted on rubber pads or resilient mats to reduce noise and vibration transmission to adjacent properties. Some systems use steel and rubber spring suspended floating slabs to facilitate later changes. ^UoS

Flow of Metal (rail)

Rolling out of steel on the crown of a rail toward sides of the head. More common on the low side of a canted curve, located where trains travel frequently at less than balancing speed. (UK: Lipping)^UoS

Flow Separation

Loss of continuity of airflow along parts of the train’s outer surface.^UoS

Fog Signal

See Detonator.^RT

Formation

Material provided between the ballast and the subgrade to either increase or reduce the stiffness of the subgrade, or to prevent overstressing the subgrade. Some use the term to describe embankments and similar structures which are not part of the preexisting ground.^RT+UoS

Four Foot (UK)

The space between the running rails measured from the edge of the baseplates underneath the rails (rail chairs). The most dangerous place to be on a railway.^UoS

Four Rail System

A now almost unique current collection system used by London Underground which has separate positive and negative current rails. The same system was used by the LNWR and the Mersey Railway at one time. The usual 3rail method of conducting the return current via the running rails is replaced by a fully insulated system using separate positive and negative rails. Originally used to reduce the risk of stray currents causing damage to nearby utilities and structures through electrolysis. The system has the disadvantage of requiring special fault detection as earth faults do not cause current to switch off automatically (see also: conductor rail).^UoS

FRA

The Federal Railroad Administration. An agency of the U.S. Department of Transportation with jurisdiction over matters of railway safety and research.^UoS

Fracture, Detail

A progressive transverse fracture originating in the head of a rail, caused by inclusions in the original metal. Cleaner steels means this flaw is on the decline. (UK: Tache Oval)^UoS

Franchise

An agreement between the Franchising Director and a train operator to run particular passenger services for a defined period.^RT

Franchise Director

Officer appointed under the Railway Act 1993 to franchise passenger services.^RT

Fredy

A device for detecting trains approaching level crossings without the use of a treadle. Unfortunately, vulnerable to leaf contamination, and so being replaced by treadles.^RT

Freight Upgrade

An initiative to secure future freight revenue and to protect passenger revenue, through infrastructure gauge improvements and routing strategy, particularly on the WCML. ^RT

Frog (US)

A track structure used at the intersection of two running rails to provide support for wheels and passageways for their flanges, thus permitting wheels on either rail to cross the other. (UK: Crossing)^UoS

Frog Angle (US)

Angle formed by intersecting gauge lines of the rails, or by tangents to the gauge lines at their point of intersection when the frog is curved. (UK: Crossing Angle)^UoS

Frog Number (US)

Onehalf the cotangent of onehalf the frog angle, or the number of units of centreline length in which the spread is one unit. The rate of spread of the gauge lines at the frog. The number of units of length for a spread of one unit.^UoS

Frozen Joint

A joint so tight that the rails cannot move as temperature varies. ^UoS

Fuel Oil

Diesel and other similar hydrocarbon based oils used as a fuel for train motive power.^RT

G...

Gain Amplification [especially of a signal].^RT

Gangway

Flexible structure provided at vehicle ends where necessary to provide access from one vehicle to another. The gangway is divided between the two adjacent vehicles and is normally closed off when the vehicles are uncoupled.^UoS

GasTurbine Electric Locomotive

A power unit in which a gas turbine drives electric power, normally alternators supplying current to electric traction motors on the axles.^UoS

Gauge

The distance between the inner running faces (gauge lines) of the two rails, on the same track. Also used to describe the "envelope" through which trains’ profiles must fit this is the structure gauge (US spelling "gage".^RT+UoS

Overview of Common Track Gauges:

Broad gauge (Spain):	1674 mm	5'5 9/10^th"
Broad gauge (Portugal):	1665 mm	5'5 11/20th"
Broad gauge (Ireland):	1600 mm	5'3"
Broad gauge (Finland):	1524 mm	5' exactly
Broad gauge (former USSR):	1520 mm	5'
Standard gauge (Worldwide Application):	1435 mm	4'8 1/2"
Narrow gauge (Cape gauge):	1067 mm	3'6"
Narrow gauge (meter gauge):	1000 mm	3'3 37/100"
Narrow gauge (Latin America)	950 mm
Narrow gauge (Austria):	750 mm

Gauge Line

A line five eighths of an inch, about 15mm below the running surface of a rail on the side of the head nearest the track centre; the line from which measurements of gauge are made. Gauge, narrow (see Narrow Gauge.)UoS

Gauging (of track)

Bringing two opposite rails into their correct relative positions as regards to their distance apart.^UoS

Gemini

A system for resource control of multipleunit trains.^RT

Gemini for Non Integrated Unit Stock

A Windows frontend facility for Resource Controllers to manage the day to day operation of their fleets. Adopted by Virgin Trains. Users of GENIUS withdraw from TOPS/POIS/EDTA.^RT

General Purpose Radio System (GPRS)

Implementation of PSS using mobile radio communications.^UoS

General Utility Van

A type of parcels van, some of which were converted by Railtrack for leaf fall track clearance.^RT

Geographic and Infrastructure Systems (GEOGIS)

A major database of railway infrastructure assets containing information on the physical location of track, buildings and structures.^RT

Geographic Information System (GIS)

High quality database for assets using exact geographic information for object location, in most cases referenced to a national grid system. May include full mapping information. Generally of a relational type and based on a standard software such as ORACLE or ARCINFO.^UoS

Global Positioning by Satellite (GPS)

Navigation based on measuring time delays of signals received from four or five satellites. See also DGPS.^UoS

Global System for Mobile Communications (GSM)

Internationally agreed standard and protocols for mobile radio (telephone type) communications using cellular arrangements to maximise use of the frequency spectrum. European standard. ^UoS

Global System for Mobile Communications for Railways (GSMR)

Specialised GSM cellular Personal Mobile Radio (PMR) implementation for railways using the 900MHz band and with a higher level of reliability and safety and more features than GSM.^UoS

Goods Line

A line which has not been signalled to the standards required for running passenger trains.^RT

Grade US

Term for sloping track. UK terms are gradient or "bank". "At grade" means level track. ^UoS

Grade Crossing (US)

See level crossing.^UoS

Grade Line (grade)

(1) The line of a profile representing topofrail elevations of the track.
(2) A series of staked elevations transferring this line to the ground or roadbed.^UoS

Grade Rail

The rail first surfaced to track elevation; the line rail on tangent track, the inner or low rail on curves.^UoS

Grade Separation

A term applied to the use of a bridge structure and its approaches to divide or separate the crossing movement of vehicular, pedestrian or other traffic, by confining portions thereof to different elevations. See Flyover and Dive under.^UoS

Green Zone

An area of protection for workers, which separates work on the railway line from train movements. The simplest way of arranging such a zone is to stop movements of all trains on all lines at the location concerned. Fencing off the work area may be an accceptable alternative but requires reduced speed operation. ^.RT

Gricer

Slang term for a train enthusiast.^RT

Gricex

Slang term for a special train, often a steam special. The word is derived from ‘gricer’ and ‘x’ meaning excursion.^RT

Gross Project Code

Records the full amount of income invoiced by a business unit to a customer prior to allocating income to the interunit account code of the appropriate business unit.^RT

Ground Disk

Small shunting signal at low level (often called a "dolly" or a "dummy").^RT

Ground Frame

A small lever frame to operate points and signals, usually mounted at ground level. Sometimes a small switch panel which works little used connections at locations remote from a signal box.^RT

Ground Position Light

A low level shunting signal displaying lights rather than a disc.^RT

Group Standard

A document published by the Safety and Standards Group of Railway Safety as a Railway Group Standard or a Railway Group Code of Practice.^RT

Guard

Senior Conductor, Conductor or Train(wo)man.RT

Guard Rail (US)

See also: Check Rail. Guideway (UK) Running surface with mechanical or electrical guidance function for nonrail guided transport. (US) Supporting structure for a rail track. ^UoS

H...

Hackwall (US)

The section of wall rising from the surface of an abutment.^UoS

Hand Points

Turnout (points) which is worked manually by an adjacent independent lever.^RT

Handite Hand Held Sandite Applicator

(a trade name used by Chipman Rail).^RT

Harm

Means harm to the health of living organisms or other interference with the ecological systems of which they form part. Also, in the case of man, includes offence caused to any of his senses or harm to his property. Harmless has a corresponding meaning.^RT

Hazard

Situation with potential to cause harm or loss.^RT

Hazpak

Training course for drivers of vehicles carrying dangerous substances in packages.^RT

Head Block (switch) (US)

A pair of ties (or, in old types of turnouts, a single tie) used to support the switch points operating mechanism and the switch stand.^UoS

Head Code

An obsolete term for the Train Reporting Number. The headcode is a unique code to identify each train; it is made up from the Class of train, followed by its destination; and finally its number designated by track access (eg. 1A30 = a Class One express train, travelling towards London, No. 30). The range of letters used in the train reporting numbers are too detailed to list here.^RT

Head Rod (US)

The switch rod nearest the toe of a switch, usually placed between the two head block ties.^UoS

Head End Power

A system of furnishing domestic electric power (hotel power) for a complete railway train from a single generating plant in the power unit, excluding traction power.^UoS

Headspan Wire

A wire suspended across the tracks and from which the OLE is suspended.^RT

Headway

The time interval between the passing of the front ends of successive multiple units or trains moving along the same lane or track in the same direction. ^UoS

Heater, switch

A device for melting snow at switches by means of steam, an electric current, gas jets, or oil.^UoS

Heat Treated Rail

Rail subjected to accelerated cooling or other heat treatment after rolling with the intention of achieving specified mechanical properties.^RT

Heavy Haul Railway

large capacity train haulage of bulk commodities. Normally uses unit train format.^UoS

Heavy rail transit

A mode of rail rapid transit generally characterised by high passenger carrying capacity , fully gradeseparated construction, operating on exclusive rights of way, and station platforms at the floor level of the vehicles.^UoS

Heavy rail vehicle

A vehicle operating on a heavy rail transit system. Typically, electrically propelled, bidirectional, capable of operating in multiple unit, and designed for rapid, highlevel boarding and discharging of passengers.^UoS

Heel Block (switch)

A block which spans joints and fills the space between adjacent rails at the heel of a switch, joined with outside splice bars by continuous bolts to form a unit joint. Also serves as a foot guard.^UoS

Hertzian Contact

The pressure distribution in the contact patch.^UoS

High Speed Interoperability

Requirement placed on highspeed rolling stock and operational practice to allow cross border operation without locomotive and new changes. ^UoS

High Street Environment

A worksite outside the area of an Infrastructure Manager’s (Network Rail’s in Britain) Controlled Infrastructure and which may not impinge upon railway operations^RT

Highway Crossing Protection (US)

An arrangement of one or more highway crossing signals, with or without gates, to protect highway traffic. (UK: level crossing protection)^UoS

Hollow Bearer bearer (Sleeper)

, fabricated from steel or cast, with space internally to accommodate switch drive mechanisms and detection devices. Can also be used to route cables across a track.^UoS

Home Signal

The first stop signal on the approach to a (non Track Circuit Block) signalbox. See Track Circuit Block. ^RT+UoS

Hot Axle Box Detector / or Detected

This is a trackside temperature detector, which warns a signal box of an overheated bearing; as it counts the passing wheels and indicates which axle is faulty, if one axle or wheel is hotter than the others on the train.^RT

Hotel Power

That part of a train’s power consumption which is needed to power air conditioning, lighting, heating and kitchen facilities on a train. Often greater than 1020% of the total energy requirement. ^UoS

House Track (US)

A track alongside of or entering a freight house; used for cars receiving or delivering freight at the house. (UK: industrial sidings)^UoS

Human Resources System

A computer system replacing NPS and PEARLS.^RT

Hunting (UK)

The sinusoidal oscillation of a bogie or wheelset at speed caused by wheelset conicity and yaw stiffness and initiated by irregularities in the track or wheels. Different designs "hunt" in different ways and under different conditions. Below a critical speed, the oscillations decay away. Above the critical speed the oscillations increase, and this can have a damaging effect on rails or may lead to the train being derailed. Suspension design often affects ride as much as anything and the whole science of bogie design can be a bit of a black art. (US: boxing) ^UoS

I...

IECC

System Monitor a facility for reporting errors to the Integrated Electronic Control Centre.^RT

Impact Coefficient

An enhanced loading designed to simulate occasional exceptional or accidental loads to which a sleeper may be subjected in service^RT

Impedance bond

An electrical circuit at installed at points on the track where track circuit frequencies or codes change in electric traction areas to separate signal and traction current. (See also: Bond)^UoS

Implementation

The undertaking of physical works to deliver the detailed design.^RT

Improved Manufacturing Performance Through Active Change and Training

A Westinghouse partnership initiative.^RT

In Advance Of

Ahead of in the (normal) direction of travel.^RT

In Rear Of

Behind in the (normal) direction of travel.^RT

Incident

An unplanned event which, under different circumstances, could have resulted in:

physical harm, injury or disease to an individual;
damage to property;
a near miss;
loss;

or any combination of these effects.^RT

Insulated switch

A switch in which the fixtures, principally the gauge plates and the switch rods connecting one rail to the other, are provided with insulation so that electric currents will not be shunted. Also, the turnout rail must contain an insulating joint.^UoS

Insulating rail joint

Sometimes called Insulated Joint. A rail joint designed to stop the conduction of electric current between two lengths of rail, as at the end of a track circuit. Normally consists of insulated fishplates, end postand insulating sleeves for the rail bolts.^UoS

Integrated Electronic Control Centre (IECC)

Train control centre (power signal box) with responsibility for a hundred or more route km where all data displays and most safety interlocking are computer controlled. Many functions are carried out automatically using train describers and automatic route setting (ARS) based on TRUST Train Ids. Operators are only involved in situations where there is disruption. IECCs exist at London Liverpool St., Merseyside, Tyneside, York and elsewhere. ^UoS+RT

Interfrigo

An operator of privately owned wagons. ^RT

Interlocking

In signalling, a system to prevent the setting up of conflicting routes by logically linking points and signal operation. At first interlocking of actions was achieved mechanically through the locking frame, then electromechanically by relays in the signal box. Now, interlockings are largely computerised using a two in three voting system, diverse hardware and software or protocols. Also note the term SSI (solid state interlocking). Computer hardware and software must be safety approved. In the US, the term Interlocking refers to an area where junctions and signals are under the control of a signal cabin or "Tower". ^UoS+RT

Intermediate Block Home (IBH)

Signal stop signal controlling one exit from the section in the rear into the block section ahead, originally at an intermediate section signal box.^RT+UoS

Intermediate Block Section

A track circuited section of line between the section signal and the Intermediate Block Home Signal, both of which are worked from the same (Absolute Block) signal box.^RT

Intermittent ATP (IATP)

System of automatic train protection where trains receive information from the trackside at regular intervals. In between these fixed locations, trains cannot receive any updates.^UoS

Intermodal Car

A rail wagon designed specifically for handling piggyback trailers or containers, or both.^UoS

Intermodal Traffic

Freight moving via at least two different modes of transport, e.g., trucktorail.^UoS

Interval

The actual difference in time between trains.^RT

Invitation To Tender

A collection of documents issued to one or more potential suppliers or contractors to invite commercial bids to undertake specified tasks.^RT

Iris

A test coach operated on the railway to test the strength of radio signals received via the National Railway Network Radio system.^RT

J...

Jerk

The rate of change of acceleration with time. Units are mass per time cubed. Passenger comfort criterion. Maximum level allowed in the UK is 0.7m.s³. ^UoS

Joint

The junction of two rails or of like materials in bridge members. ^UoS

Joint bar (US)

A steel angle bar or other shape used to fasten together the ends of rails in a track. They are used in pairs, and are designed to fit the space between head and flange (fishing space) closely. They are held in place by track bolts. Also, called angle bar, rail joint bar, and splice bar. (UK: fishplates)^UoS

Joint Industry Cost

Costs incurred by Network Rail on behalf of customers and "passed through" to them.^RT

Joint Line

Any route where the line was formerly owned by two or more companies.^RTWP

Joint Line

The route from Doncaster to Peterborough via Lincoln and Spalding; its title when built was the Great Northern and Great Eastern Joint Railway.^RT

Jointed Rail or Track

A method for joining lengths of rails with steel members (fish plates) designed to unite the abutting ends of contiguous rails. Normal length of 60 ft but can be 45 or 30 ft lengths.^UoS+RT

Journal Entry

Debit or credit to a general ledger account with a balancing debit or credit to another general ledger account.^RT

K...

Key Performance Indicators

These are financial or other indicators used to monitor how well the business is doing in terms of satisfying its Critical Success Factors (order qualifying and order winning criteria.)^RT

Kinematic Envelope

The volume of space swept through by a train in motion. It takes account of overhang on curves, tilting, etc thus differing from the static loading gauge The kinematic envelope must be smaller than the structure gauge.^RT+UoS

L...

Ladder Track

A track connecting successively the tracks of a yard. ^UoS

Lateral Track Force

Sideways force on the track generated by a vehicle on a curve.^UoS

Lead Business Unit

The business unit responsible for sending an invoice for all services to a TOC, regardless of which business unit will ultimately recognise the income. ^RT

Lead track

An extended track connecting either end of a yard with the main track. ^UoS

Leeds Northern

Slang title given to the line between Northallerton and Eaglescliffe. This line ran from Wortley Junction through Horsforth, Harrogate, Ripon, Northallerton, Eaglescliffe, Stockton, Hartlepool and Sunderland to Newcastle. It was owned and operated by the "Leeds Northern Railway" from 1847 until 1854, when it was taken over by North Eastern Railway (NER) but (surprisingly) Leeds Northern title lives on in everyday railwayman’s language.^RT

Level Crossing (UK)

The point where a railway line and a motor vehicle road intersect at the same level. Protection levels include (i) signage, (ii) road traffic signals, (iii) flashing lights, (iv) automatic half barriers, (v) automatic full barriers, (vi) manually operated barriers. Level crossings may be monitored locally or remotely using CCTV etc. (US: Grade Crossing).^UoS

Lever Collar

A device, often of carved wood, placed over a signal lever or other control to remind the operator of it being restricted or out of use.^RTWP See also Reminder Appliance.^RT

Licensed Operator

A company or organisation who is granted a licence by the Rail Regulator to operate rail services, and to operate vehicles on the track, under terms and conditions defined by the Rail Regulator.^RT

Light Loco

Term used to describe a locomotive running on its own without a train (usually to or from a depot for maintenance etc. (sometimes called a Light Diesel or Light Electric, according to type)^RT

Light Rail Transit

A mode of rail transit characterised by its lower passenger carrying capacity and the ability to operate on its’ own rightofway (reservation, side or central) or to share road space with other traffic. Nowadays light rail vehicles (LRVs) are much favoured as an alternative to full blown subway or underground (heavy metro) lines for urban rail systems due to their reduced construction costs. Passengers may board or alight from track level or using vehicle floor level platforms.^UoS

Light Rail Vehicle (LRV)

Modern generic term for tram or streetcar. An electrically powered rail vehicle using rails embedded in the roadway (operating in mixed traffic ) or using dedicated rail tracks, or a combination of the two as in Manchester, Sheffield, and many other European and US cities. Modern LRV design concentrates on low floor construction to make access easier for passengers and to reduce the height of platforms at stations. Much innovation is appearing in the industry as a result. Apart from recent developments in Germany, LRVs are electrically powered , generally from overhead supplies. ^UoS

Light Steam

Sufficient steam pressure to work injectors, lubricators and brakes but not more than 75% of maximum boiler pressure.^RT

Like For Like Renewal

The removal and restoration or refurbishment of an item where the work does not require any fundamental design change to the Infrastructure. This may involve restoring or refurbishment of the original item or replacing it with an operationally equivalent new item.^RT

Limit of Movement Authority (LMA)

The instantaneous distance that a train can travel before encountering a stop signal. ^UoS

Line Capacity

The maximum possible number of trains capable of being operated over a line in one direction. Usually expressed as trains per hour. The theoretical (maximum) capacity will depend on the trains running speed and braking capacity and on how the signalling is arranged. ^UoS

Line Light

An indicator on the drivers desk of an electric train that current is being drawn from the overhead wires. When the line light is lost (and cannot be re

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