Jargon Buster

The jargon buster aims to give simple, plain English explanations of typical words and phrases used in the rail industry – to help us all understand what we read or hear day-to-day.

If you’ve heard a word or phrase you don’t know, check to see if it’s on the list below. If it isn’t, please send it in, giving as much context as possible. We will do our best to find out what it means and publish an explanation here.

You can also add terms yourself. If you do, please include the word or phrase itself, plus a short explanation of what it means and when it might be used. Please email suggestions here 

There are also terms used on this site as defined in Network Rail’s Infrastructure Projects organisation that maybe of more general use and help you in your understanding.


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  • a

  • A2CO
    A2CO – Authority to Change the Organisation is an approved request to restructure a team or department, including changing the reporting lines, location, job titles etc. This topic is covered on Connect within HR Online.
  • A2I
    A2I – delegated Authority to Incur grants a permanent employee within Network Rail with the ability to allow payments to be made for goods and / or services on behalf of the company
  • ABCL
    Automatic Barrier Crossing. Locally monitored by train crew.
  • Absolute Block Signalling
    A signalling system that allows only one train to be in the Block Section at the same time. Normally, no train is allowed to enter a section occupied by another
  • AC
    Alternating Current- Electricity flow
  • ACC
    Annual Capability Conversation - is the process Network Rail uses to review an employee's track competence and ensure they meet the necessary requirements to hold the competence.
  • Access Agreement
    An agreement regulated under the Railway Act 1993 setting out the terms and conditions under which companies/operators obtain access to railway track, stations and certain types operators obtain access to railway track, stations and certain types of depots.
  • Access Charge
    The charge paid by railway operators for access to rail facilities, that are the subject of an access agreement.
  • ACI
    Automatic Code Insertion. The means by which, when a train terminates, the next working of its stock is automatically picked up by the signalling areas.
  • ACM
    asbestos containing material
  • ACOP
    Approved Code of Practice  gives practical advice on how the law is to be complied with
  • ACS
    Approach Control Signal
  • ADD
    Automatic Dropping Device - (Pantograph)
  • AFA
    Access For All
  • AFC
    Anticipated Final Cost
  • AFR
    Accident Frequency Rate- measure previously used in industry to measure safety performance
  • AHB
    Automated Half Barrier crossing
  • AHBC
    Automatic Half Barrier Crossing.
  • AHD
    Aggregates Handling Depot
  • AIP
    Approval in Principal
  • AiTL
    Assessment in The Line - a way of checking, and confirming competence though line management
    As Low As Reasonably Practicable- health and safety term to indicate risk has been reduced to the point where cost exceeds the benefits
    All level crossing risk model
  • ALO
    Any Line Open. This is to clarify the requirement that any open line that has the potential to be fouled by the work being carried out on the infrastructure by construction plant or machinery must be assessed and controls put in place to ensure that the works will not affect the safe(...)
  • AMP
    Asset Management Plan
  • AOCL
    Automatic Open Crossing – locally monitored by train crew
  • AOCR
    Automatic Open Crossing – remotely monitored
  • AOM
    Area Operations Manager
  • ARM
    Active or Asbestos Risk Management
  • ARS
    Automatic Route Setting: information is sent to three computers, two of which have to agree an outcome before the route can automatically be set for the train.
  • ARTP
    Association of Rail Training Providers
  • ASC
    Area Signal Control
    Associated Society of Locomotive Engineers and Firemen: union which represents many train drivers
  • ATFS
    Auto Transformer Feeder Station
  • ATOC
    Association of Train Operating Companies- which became the Rail Delivery Group (RDG) founded in 2017
  • ATWS
    Automatic Train Warning System
  • Authorised Walking Route
    A specially designated route for the use of personnel when walking to and from their place of work. To include site depots, on site, when carrying out railway duties or going to and from their booking-on point
  • Automatic Level Crossings
    Includes AHBC, ABCL, AOCL and AOCR level crossings as well as those protected by miniature red/ green warning lights
  • Automatic Warning System
    A system provided to drivers to give an audiovisual indication in the cab of the status of the signal ahead. This system briefly works as follows; as the train approaches the signal it passes over a ramp between the rails, in which are placed two electromagnets (or a permanent magnet (see(...)
  • Axle Counter
    It counts the number of train wheels passed through it. provided at starting and ending of a station to conform the total passed station without leaving any boggies
  • Axlebox
    This provides the bearing between the axle and on all railway vehicles frame. These were usually simple bearings designed to take the load (for driving wheels) of the alternating piston thrusts as well as the weight of steam locomotive. They were mounted in vertical slides within the frames(...)
  • b

  • Back Board
    Slang for a distant signal.
  • Backlock
    Physical release to allow replacement of a signal route (physical time out).
  • Ballast
    Graded stone sub-base used for drainage and support of the track.
  • Ballast Cleaning
    Removal of existing ballast using a machine which grades the excavated ballast, returning good stone to the track and taking fine stone and spoil for disposal.
  • Ballast Train
    A train of wagons to and from work sites conveying track ballast or any other equipment needed within a possession.
  • Bang Move
    Slang: A wrong direction move of a train
  • Bang Road
    A slang term describing train movements against normal direction.
  • Banker
    Assisting locomotive that pushes from the back of a train.
  • Banner Repeater
    Signal whose function is to repeat the indication shown by another when the latter cannot be seen by the driver (see Repeater Signal).
  • BAP
    Biodiversity Action Plan
  • Bardic Lamp
    A battery operated lamp with a coloured filter which could be rotated to show white, red, yellow or green aspects.
  • Barrier Wagon
    A vehicle used mainly in dangerous goods trains to separate the wagons carrying dangerous goods from other parts of the train.
  • Barrow Crossing
    Level crossing at the end of a station platform for use by (or under the supervision of) rail staff only.
  • Baseplate
    Metal casting which supports and holds a flat bottom rail on a sleeper.
  • Bay Platform
    A platform with buffer stops at one end used for trains terminating at the station.
  • BBRM
    Balfour Beatty Rail Maintenance Limited. (Track Renewals).
  • BBRR
    Balfour Beatty Rail Renewals.
  • BCR
    Business Critical Rules
  • Bell Code
    The sequence of bells (block bells) used to communicate between signal boxes using a standardized code
  • Berth - track circuit
    A name occasionally used for a specific track circuit.
  • Berth Offset
    Difference between the time a train actually occupies a track circuit and the time recorded in TRUST for the event (see TRUST).
  • Bi-directional Line
    A line that is signalled to take trains in both directions.
  • BIM
    Building Information Modelling [aka Better Information Management]
  • Black Box
    Equipment fitted into the Driving Cab of some Units (usually the newer rolling stock) which records train speed/brake applications/AWS indications/TPWS activations received etc on each journey. Also know as O.T.M.R., (On Train Monitoring Recorder) the contents of the "Black Box" can be(...)
  • 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
  • Block Instrument
    An electrically operated indicating device used in a signalbox. The instrument is connected with a similar device in an adjacent signalbox, and can be set to indicate whether or not the block section between the two signalboxes is occupied by a train.
  • Block Joint
    Also known as an insulated rail joint. A rail joint in which one rail is electrically insulated from an abutting rail.
  • Block Section
    The section of line between the section signal of one signalbox and the home signal of the next signalbox ahead
  • Block Token
    A device carried by a driver as his authority to run over a single line worked by the Electric Token Block System.
  • Blocked Line
    A line / or a portion of line that is closed to the passage of trains
  • Board
    Slang for a signal
  • Bobby
    Traditional slang for a signaller (the original signallers were actually Railway Police Officers).
  • Bogie
    A wheeled undercarriage pivoted below the end of a rail vehicle
  • Bond
    A wire connection between the rails to ensure electrical continuity.
  • Bowmac
    “Panel level crossings are used so that the panels can be removed to allow maintenance of the track. The Bowmac design of panel was the standard product used by BR for most of the 1970s and 1980s.” Sometime mispelt as Bomac. Thanks to Iain King
  • Box of Eggs
    A portable device with lamps to test whether the conductor rail is still energised. This is also known as a Conductor Rail Test Lamp Set.
  • BSN
    Bridge Strike Nominee - A person who has been certified as competent to implement the procedures for reopening lines after a bridge strike
  • BTP
    British Transport Police
  • BTRC
    Booster Transformer Return Conductor
  • Buckled Rail
    A rail that has been buckled by heat expansion
  • Buffer Stop
    Railway-vehicle stopping-devices located at the end of a siding or terminating platform
  • c

  • Cab
    The driver's compartment of a locomotive or railcar, etc
  • CAF
    Change Acceptance Form
  • Cant
    The dimension by which the outer rail on a curve is raised above the inner rail.
  • Cantilever
    A type of overhead line support
  • Cantrail
    Strip on the side coach above the window line where the body side meets the roof
  • CAPE
    Originally a railway telegram code to indicate that one or more trains will not now run, it is sometime still used as slang to mean anything that is cancelled.
    Capital Expenditure
  • CASR
    Cardiff Area Signalling Renewal
  • Catch Pit
    A Catchpit is essentially an empty chamber with an inlet pipe and an outlet pipe set at a level above the floor of the pit. Any sediment carried by the system settles out whilst in the Catch-Pit, from where it can be periodically pumped out or removed. Usually covered by Grill or Man hole cover
  • 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 running back without authority or out of control. These were a requirement before all vehicles had automatic(...)
  • Catenary
    Term given to overhead wires which support the contact wire on overhead line equipment
  • CBI
    Computer Based Interlocking
  • CCIL
    Control Centre Incident Log - provides real time updates of all railway related incidents
  • CCTV
    closed circuit television
  • CD
    Close Doors platform indicator. A special signal to a train driver that a train is ready to depart from a station.
  • CDG
    Competence Development Group
  • CDM
    Construction Design & Management Regulations
  • CESS
    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. //
  • Chain / ch
    A unit of measurement equalling 66 feet, or 22 yards, or 100 links. Equal to 20.1186 metres. Still used on rail infrastructure to indicate location
  • CIP
    Competent Independent Person
    CIRAS is an independent, not-for-profit confidential reporting service for the transport sector. People can speak up about their health, safety and wellbeing concerns to CIRAS in complete confidence. CIRAS shares the concerns with the relevant company, and then shares the company response with(...)
  • CIS
    Customer Information System - station information screens
  • Clamp Lock
    A point operating mechanism, which locks the points by directly clamping the closed switch rail to the stock rail
  • Close Call
    Anything that has the potential to cause harm or damage This includes the potential to: •Harm a person including minor, major injuries, and fatalities •Harm the environment and/or protected species •Damage railway infrastructure, plant, vehicles, tools and equipment. (Not to be Confused(...)
    Control of Substances Hazardous to Health
  • COSS
    Controller of Site Safety
  • Country side
    A term used to describe a specific point of a location, for the point of a location furthest from London.
  • CPC
    Circuit Protective Conductor
  • CPP
    Construction Phase Plan
  • CRE
    Contractors Responsible Engineer
  • CRF
    Change Request Form
  • Cross Span Wire
    A wire stretched across tracks holding the overhead line equipment in this desired position
  • CRT
    Critical Rail Temperature - The rail temperature to which CWR may be allowed to rise before measures to protect traffic must be taken. The CRT will depend on the stress-free temperature of the rail and the quantity and degree of consolidation of the ballast.
  • CS
    Carriage Sidings
  • CSR
    Cab Secure Radio
  • CT
    Current Transformer
  • Culvert
    Small bridge or pipe carrying a stream under a railway or road
  • CWR
    continuously welded rail
  • Cyclic Top
    Cyclic Top occurs when a dip in a rail causes the suspension of a vehicle passing over it to bounce. The track at the end of the bounce then receives an impact loading that can create a second rail dip and, as that second dip deteriorates with successive impacts, trains will then bounce a(...)
  • d

  • DC
    Direct Current. relating to Electrical flow, found in the Third (3rd) and Fourth (4th) rail systems to the South of London and the London Underground network
  • DCP
    Designated Competent Person(s)
  • De-icing Train
    A special train fitted with equipment for clearing snow or ice from conductor rails
  • Deadman's Pedal/Handle
    Slang term for Driver’s Safety Device: device on traction rolling stock that will stop the train if the driver becomes incapacitated.
    Derived from former telegraphic code indicating a failed train
  • DEMU
    Diesel Electric Multiple Unit
  • DEP
    Designated Earthing Point
  • Depot
    A complex of sidings, buildings, platforms, etc. where transhipment, stabling, servicing, repairs and other such activities are undertaken.
  • Derailment
    A derailment is deemed to have occurred when the wheel flange has left the rail alignment and the wheel tyre has lifted from the railhead
  • Detonator protection
    Carrying out full train protection in the event of a breakdown, including the guard walking back a set distance from the rear of the train and placing detonators to alert any trains following. Detonators are also used to mark/protect work site  posssesions
  • Dets/Detonator
    A small explosive charge set off by the wheel of a train passing over it. Detonators consist of a small metal cap attached to two soft metal strips which would be used to clip it on top of a rail. Used in emergencies to provide a clear audible warning to drivers. Carried on all trains for use(...)
  • DFL
    Down Fast Lane
  • DfT
    Department for Transport
  • DLR
    Dockland Light Railway
  • DMMU
    Diesel Mechanical Multiple Unit
  • DMU
    Diesel Multiple Unit
  • DNO
    Distribution Network Operator - this relates to electrification and power supplies for stations etc.
  • DOO
    Driver Only Operation
  • DOS
    Dimensions of Safety
  • Downline
    That line on a multi-track main line where the direction of travel is away from London- or an allotted City
  • DPE
    Designated Project Engineer
  • DPS
    Depot protection System
  • DRA
    Driver’s Reminder Appliance: a device in the cab to enable the driver to set a reminder that the signal ahead is at danger
  • DRAM
    Director Route Asset Management
  • Drop Shunt
    An S andT term for test on a track circuit, the effect of which will be to make the track circuit show occupied
  • DRS
    DRS - Dynamic Route Setting
  • DSD
    Driver’s Safety Device: device on traction rolling stock that will stop the train if the driver becomes incapacitated. Popularly knows as the ‘Deadman’s Pedal’ or ‘Deadman’s Handle
  • DSL
    Down Slow Line
  • DU
    A Network Rail Delivery Unit
  • DWWP
    Delivering Work Within Possessions
  • e

  • E&P
    Electrification and Plant (Power)
  • EAS
    Engineering Access Statement (used to be known as Rules of Route) - an agreement for disruptive access with the TOC to allow the planning of services around a possession
  • ECO
    Electrical Control Operator
  • ECR
    Electrical Control Room: responsible for control of current in the overhead lines and third rail.
  • ECRO
    Electrical Control Room Operator
    Electrical Control Room Operator Manager
  • ECS
    Acronym for Empty Coaching Stock, used to describe passenger trains not currently carrying passengers
  • EEN
    Examining Engineer’s Nominee (can authorise opening at linespeed for bridge strikes).
  • EGI
    Equipment Group Identifier
  • EGIP
    Edinburgh - Glasgow Improvement Programme
  • EIA
    Environmental Impact Assessment
  • EiS
    Entry into Service
  • Electrified Line
    A line which is electrified either by 25,000 volt AC overhead lines, or by 750 volt DC conductor rail.
  • ELR
    Engineer’s Line Reference- a way to identify location/ structure on plans and directories
  • Embankment
    A section of railway line where the surrounding countryside is at a lower level than the line and the ground has been built up to put in the line.
  • EMC
    Electromagnetic capability EMC aims to ensure that equipment items or systems will not interfere with or prevent each other's correct operation through spurious emission and absorption of the unwanted effects (electromagnetic interference - EMI) from voltages in adjacent cables or equipment.(...)
  • EMU
    Electric Multiple Unit
  • EPR
    EPR - Engineers Possession Reminder
    European Rail Traffic Management System
  • ES
    Engineering Supervisor
  • ESR
    Emergency Speed Restriction- An unplanned reduction in train speed imposed between defined locations along a track. A speed restriction not shown in the Weekly Operating Notice.
  • f

  • Facing Point Lock
    Equipment that physically locks points so that they cannot move
  • Facing Points
    Facing Points are points which have signalled train movements over them in the facing direction which is the diverging direction where there may be a choice of destination. N.B. only one destination may be valid for a signalled route for example at trap points or at the end of a single or(...)
  • Failed
    term for a broken down train
  • FDM
    Frequency Division Multiplexing
  • Feather
    Slang term for the row of five white lights mounted at an angle above or beside a (cleared) colour light signal to give an indication of route.
  • FFF
    First Filament Failure: refers to a failure in a signal lamp which has more than one filament for safety. The bulb must be replaced, but the signal works normally and cautioning of trains is not necessary.
  • Fish Plate/fishplate
    Steel plate to secure the ends of two rails together (in jointed track).
  • Flagging
    A system of signalling trains manually with flags during breakdown or suspension of the normal signalling system
  • Flank Locking
    Flank locking is a safety feature, incorporated in the signalling equipment, which then prevents signals operating on routes adjacent to other areas with a failure.
  • Flank Protection
    A means of protecting movements of trains across junctions by the setting of points (either manually or automatically) that prevent any other unauthorised movement coming into contact with it.
  • Flat
    A flat spot on the circular tyre of a wheel, usually caused by the wheel skidding along the rail when braking heavily. Causes a characteristic knocking noise and vibration in the vehicle. Also known as square wheels.
  • FOC
    Freight Operating Company
  • Fouling Point
    The point on a pair of converging tracks where the two trains would collide side on if allowed to approach together.
  • Four Aspect Signal
    A colour light signal capable of displaying four aspects. From top to bottom the lights are yellow, green, yellow, and red. A red indication means that the next section contains a train. A single yellow indication (using the lower yellow) means that the next section is clear but there is a(...)
  • Four Foot
    The area between the inner running faces of a pair of rails.
  • FPL
    Facing Point Lock: a device to ensure that points which are facing the approaching trains are locked in position
  • Frangible
    A structure or part of a structure is frangible if it breaks, shears, distorts or yields on impact so as to present a minimum hazard to an object or vehicle hitting it or some other designed stress being placed upon it.
  • FTN
    Fixed Telecom Network
  • FTS
    Failure To Stop. Passenger trains failing to stop at booked stations or locations
  • FWC
    Free Wheel Clearance
  • FWI
    Fatality Weighted Injuries/Index- method to work out safety performance
  • FWP
    Free Wheel Passage
  • g

  • Gapped
    A train stalled over a gap in the conductor rail of an electric railway is said to be "gapped". This occurs when the shoes on the train which collect the current have all lost contact with the conductor rail due to gaps left for junctions. Particularly prevalent at complex junctions such as(...)
  • Gauge
    The distance between a pair of running rails. The standard gauge is 4 foot 8 ½ inches.
  • Gauge Corner Cracking
    Running rail wall erosion.
  • GDPR
    The General Data Protection Regulation.
  • GFTN
    Global Forest Trade Network
  • GPL
    Ground Position Light: a low-level shunting signal displaying lights rather than a disc.
  • Green Card
    Common name for the green defective vehicle label, which is put on a railway vehicle considered fit to travel within limitations, ie, only to a place of repair and with restrictions on speed, braking considerations, etc.
  • Green Zone working
    An area of protection for workers that separates work on the railway line from train movements. One way of arranging such a zone is to stop movements of all trains on all lines at the location concerned.
  • Ground Signal
    A loose term for any signal set at ground level, typically shunting signals.
  • GSM
    Global System For Mobile Telecommunications
  • GSM-R
    Global System For Mobile Telecommunications for Railways.
    Give Up Possession Around Train. At the end of a possession, if an engineering train or on-track-machine needs to be moved, Give Up Possession Around Train means that all worksites are given up to allow the train or machine to be moved.
  • GZAC
    Green Zone Access Controller
  • GZAM
    Green Zone Access Manager
  • h

  • HABD
    Hot Axle Box Detector: a sleeper-mounted temperature detector, which warns a signal box of an overheated bearing as it counts the passing wheels. It indicates which axle is faulty and if one axle or wheel is hotter than the others on the train.
  • Halt or Station Halt
    A railway station with minimal facilities where trains will usually stop only on request
  • Hand Points
    points which are worked manually by an adjacent independent lever
  • Hand Signals /Hand Signaller
    Used, mainly by shunters and guards, to indicate required movements to drivers
    Health and Safety at Work Act- the health and safety law passed in 1974
  • HAVS
    Hand Arm Vibration Syndrome
    Hazard and Operability Analysis
  • Head Code
    term for the Train Reporting Number. A unique code to identify each train; it is made up of the class of train, followed by its destination and finally its number designated. Used to be displayed on the front of a train.
  • Headspan Wire
    Wire suspended across the tracks and from which the OLE is suspended.
  • HLOS
    High Level Output Specification
  • Home Signal
    The first stop signal on the approach to a signal box using the Absolute Block system of signalling
  • Hookswitch
    A manually operated electrical isolation switch in conductor rail areas for local isolation.
  • Hookswitch Pole
    A wooden-handled pole used to operate a hookswitch.
  • Hot Axle Box Detector
    Sensor mounted on the outside of the rails of a track to detect the increased radiated heat emitted by a defective axle box or bearing.
  • Hot Box
    An overheated axle box. Usually the result of insufficient lubrication, or excessive speed
  • HS1
    HS1 – UK’s first High Speed (over 140mph) line, London – Essex – Kent – Channel Tunnel
  • HS2
    High Speed 2
  • HSE
    Health and Safety Executive
  • HST
    High Speed Train
  • HV
    High Visibility or High Voltage
  • i

  • IBJ
    Insulated Block Joint: a rail joint that separates circuits
  • ICC
    Integrated Control Centre
  • ICI
    Industry Common Induction
  • IDC
    Interdisciplinary Check - a cross check across all disciplines in a project
  • IECC
    Integrated Electronic Control Centre: a power signalbox where all data displays, safety interlocking, etc. are computer controlled and under normal circumstances trains are signalled automatically according to their TRUST Train ID
  • Impedence Bonds
    Also known as a “Spider”. Prevents traction current from entering the signalling system. Prevents traction current from entering the signalling system
  • In Advance Of
    Ahead of, in the (normal) direction of travel.
  • In Rear of
    Behind, in the (normal) direction of travel
  • Incident
    An unplanned, uncontrolled event which, under different circumstances, could have resulted in an accident
  • Infrastructure
    Any fixed assets or features of the operational railway which falls within the disciplines of civil engineering, signalling, telecommunications or electric traction power supply.
  • Inside of Signal
    Standing past, ie, inside the protection of that signal.
  • Interlocking
    Interlocking of points and signals, through the locking frame in the signal box, which prevents the accidental setting up of conflicting routes.
  • Interval
    The actual difference in time between trains
  • IP
    Infrastructure Projects or Injured Person
  • ISLG
    Infrastructure Safety Liaison Group
  • IVRS
    Interactive Voice Radio System
  • j

  • JNAP
    Joint Network Availability Plans. These are plans for all Network Rail routes agreed between Network Rail and each of the Train Operating Companies (TOCs), especially focussed on the proposed category 'A' routes to uphold the Network Rail promise to reduce disruption during engineering(...)
  • Jointed Track
    Normal rail in 60ft lengths, but can be 45ft or 30ft lengths
  • Juice
    A slang term for electricity, especially traction current
  • Jumper
    a cable used for train control or term for a potential suicide
  • Junction
    The spot at which a branch diverges from the main line.
  • k

  • KGT
    A generic term to describe a road-rail vehicle.
  • KPI
    Key Performance Indicator
  • Kv
    Kilovolt - 1000v
  • l

  • Ladder
    A layout of facing and trailing crossovers enabling movements across several parallel lines
  • Leaf Fall
    Approximately five weeks in the autumn when leaves fall on the track requiring measures to assure adhesion.
  • Level Crossing
    A place where a railway and a road cross at the same level.
  • Lever Frame
    This is the tool that is usually found in the older type of signal boxes. By pulling the relevant levers, the Signaller can operate signals, points, barriers etc.
  • LFC
    Leaf Fall Contamination: the phenomenon where the action of certain types of leaves being crushed between the rail head and train wheels can cause a build-up of residue on rails can create problems such as wheel slip, impaired braking and failure in the operation of track circuits.
  • Limit of Shunt
    A position on a railway track, usually marked by a notice of such, which represents the limit for any shunting movements
  • Line Light
    An indicator on the driver’s desk of an electric train that current is being drawn from the overhead wires or third rail. When the line light is lost (and cannot be reset) it is an indication that there may be a fault. This requires immediate attention to avoid serious damage.
  • Line Speed
    The maximum speed at which traffic is allowed to run on a line.
  • Live Rail
    Another term for the conductor rail.
  • Location Box or Cabinet
    A cabinet that is found on the side of track full of electrical equipment used for S and T equipment
  • Loco
    Lifting Operations Lifting Equipment Regulations
  • LOM
    Local Operations Manager
  • London side
    A term used to describe a specific point of a location, which is nearest to London
  • Lookout
    A person appointed, when required by the COSS to ensure staff are in a position of safety for a minimum of 10 seconds. He/She will be appointed if the lines/s cannot be blocked and work has to take place whilst the lines staff are working on remain open to traffic.
  • Loop
    A line parallel to a running line, which by virtue of crossovers between the two lines, enables one train to pass or overtake another.
  • LOS
    Limit of Shunt Indicator; the limit in which a movement can proceed in the wrong direction. Normally used to get trains behind a signal to then move forward.
  • LOWS
    Lookout Warning System
    LTIFR Lost Time Injury Frequency Rate Used as a safety measure / indicator
  • LUL
    London Underground Limited
  • Lunars
    These are the white light directional indicators, advising drivers which way they are being routed
  • LWR
    Long Welded Rail: usually delivered to renewal sites in 300ft or 600ft lengths (also known as CWR).
  • LX
    level crossing
  • m

  • M&EE
    Mechanical and Electrical Engineering (or Engineer)
  • Main Line
    A railway route interconnecting locations of major importance.
  • Marker Board
    Double-sided yellow board with two vertical red-yellow flashing lights on one side and two yellow flashing lights on the other used to indicate a work site (possession). There are two types: (i) Possession (red lights) (ii) Work Site (yellow lights). Possession and work site are not(...)
  • medscreen
    To be ‘for cause’ screened for drugs and alcohol following a safety related incident
  • MEWP
    Mobile Elevated Working Platform
  • Middle Road
    Term used to describe through tracks in a station where they are not adjacent to the platforms - used for passing non-stop trains through, frequently at high-speed
  • MIMC
    Maintenance Infrastructure Manager In Charge
  • MLRI
    Multi-Lamp Route Indicator
  • MOM
    Mobil Operations Manager
  • MPV
    Multi-Purpose Vehicle; a specialist combination set for de-icing, fire fighting, water jetting and applying Sandite
  • MSD
    Musculoskeletal Disorders
  • Multiple unit
    A train which has the engines or motors built into it, and therefore requires no locomotive. These units can be coupled together, and driven from the leading cab, when they are said to be running "in multiple".
  • MVLC
    Medium Voltage Line Cover -Provides insulation for catenary, droppers and associated conductors against contact with trees, birds, wildlife or even vehicles and vandalism
  • MWL
    Miniature Warning lights - used on some footpath crossings
  • n

  • NCC
    Formerly the National Control Centre- now known as the NOC
  • NDA
    Not Described Alarm. Indication received on a Train Describer when a Track Circuit/Signal berth becomes occupied and no train I.D. is transposed. Can be caused by a Track Circuit "flicking" or a Train I.D. failing to step from the previous Signal Berth.
  • Near Miss
    A Near Miss is the term that describes an unsafe event or act specifically involving a Train or On Track Machinary or On Track plant. To be reported as per Rule Book Not to be confused with a Close Call  which is "Anything that has the potential to cause harm or(...)
  • Nest of Eggs
    A portable device with lamps to test whether the conductor rail is still energised. This is also known as a Conductor Rail Test Lamp Set or Box of Eggs
  • Net Ops
    Network Operations-  Network Rail department focussed on the operational and maintenance of the Railway
  • Neutral Section
    An arrangement of insulators in the OLE designed to ensure that two sections are kept electrically separate even during the passage of a pantograph
  • NOC
    National Operations Centre
    Non-Passenger Carrying Coach Stock; postal and parcel vehicles.
  • NR
    Network Rail
  • NRN
    National Radio Network
  • NROL
    Network Rail Online Logistics - the ordering and planning system for all railborne materials.
  • NRT
    Network Rail Telecom
  • NSC
    National Supply Chain
  • NVQ
    National Vocational Qualification
  • NX
    Entrance–exit system (signal-box control panel)
  • o

  • OC
    Object Contoller
  • OC a
    Axle Counter Object Contoller
  • occupational crossing
    A road crossing a railway by overbridge, underpass, or level crossing, where the railway runs through private property.
  • Occupied
    A track section having any part of a train upon it.
  • OCS
    One Control Switch: a method or route setting
  • OHE
    Overhead Line Equipment: the equipment suspended over the railway for supplying electricity to electric trains.
  • OHLE
    Overhead Line Engineer
  • OHNS
    Overhead Line Neutral Section
  • OLE
    Overhead Line Equipment: the equipment suspended over the railway for supplying electricity to electric trains.
    Overhead Line Equipment Master Index
  • On the Approach to
    Newer and correct Rule Book term to replace ‘In Rear Of’.
  • OOG
    Out Of Gauge
  • OPI
    Outside Party Interest
  • ORR
    Office of Road and Rail
  • OSS
    Overspeed sensor located some distance in rear of signal which will activate if train passes over it at too high a speed when approaching the signal at danger.
  • OTM
    On Track Machine
  • OTMR
    On Train Monitoring Recorder
  • OTP
    On Track Plant
  • Out of Correspondence
    A term used when a set of points show neither a normal nor a reverse detection
  • Outage
    An outage is an interruption to a service. Planned outages are those that have been scheduled and agreed in advance and the dates and times are published. These outages are used for preventative maintenance and updates to hardware and software. They are scheduled not to interfere with known(...)
  • Overbridge
    A bridge that crosses over the railway
  • Overrun
    An overrun is the unplanned delay in handing back a line to normal traffic after a possession.
  • p

  • P and C
    Points and Crossings: an alternative abbreviation for S and C (Switches and Crossings).
  • P and M
    Plant and Machinery
  • Paddle
    A tool made of wood or other insulating material that can be inserted between the collector shoe of an electric train and the live rail to isolate traction current in an emergency.
  • Paladin
    Paladin Data Extract and Reporting System: a versatile train performance measurement facility producing analysis reports focusing on train performance and delay attribution
  • Panchex
    A system for measuring train pantographs.
  • Pandrol Clip
    A clip used to hold in place the running rail to the sleeper
  • Panel
    Also sometimes called a Workstation, this is the Signaller's "workface" where the Routes and Signals for all the trains in the area of Control are set. Some smaller Boxes may have only one or two Panels, whereas Area Signalling Centres/IECC's will consist of a number of Panels each divided up(...)
  • Pantograph
    A device fitted to the roof of an electric locomotive or EMU, which is sprung upwards to make electrical contact with overhead wires.
  • PAP
    Possession Arrival Point
  • Path
    Term to describe the planned timing and route of a train. Each train is timed along a section of line at a precise moment. There is a gap before/after other services. This is referred to as "the path". If a train is late it may well lose its path, and then have to be slotted in on ad-hoc(...)
  • Pathway
    A slot of time allocated for a train to travel along the railway
  • PCB
    Polychlorinated Biphenyls  and equivalent compounds are harmful to humans and animals, particularly those in an aquatic environment or feeding on aquatic animals, because of their toxicity, persistence and tendency to accumulate in body tissue.
  • PCL
    Principal Contractor Licence
  • PD&T
    Professional Development and Training
  • PDP
    Possession Departure Point or Personal Development Plan
  • PDSW
    Planning and Delivering Safe Work
  • Peak
    Morning peak is any train arriving into London between the hours of 0700 and 1000. Evening peak is any train departing from London between the hours of 1600 and 1900. Also a period where all passenger charter trains run.
    Paladin Data Extract and Reporting System: a versatile train performance measurement facility producing analysis reports focusing on train performance and delay attribution
  • Peg up
    Slang for giving a Line Clear to the box in the rear when working in Absolute Block regulations
  • Period
    A 28-day period, as defined by Network Rail.
  • PGI
    Planned General Inspection: Escalators and all similar public equipment (lifts, travelators etc) are inspected daily by managed station staff as part of the planned general inspection daily regime
    Person in Charge of a Possession
    Old Term- Person in Charge of work
  • pilot
    A person appointed to guide a driver of a train over a line with which he is not familiar or under special circumstances where the movement of trains is restricted. Or a member of staff with sole responsibility for authorising trains to move through an area that is subject to wrong-road(...)
  • Plain line
    When part of a set of Points or crossover are removed preventing crossing movements being made through them and effectively making the route affected set for "straight running" only.
  • PLB
    Possession Limit Board
  • PLJI
    Position Light Junction Indicator
  • PLOD
    Patrolman’s Lockout Device (trackside staff protection system); a device which, when used with the Signaller’s permission, returns a bi-directional line to a single directional line
  • PnB
    Personal or Physical Needs Break: a guaranteed break in a Driver’s turn of duty when  free from duty.
  • POE
    Point Operating Equipment
  • Point Blades
    The movable parts of the rails in a set of points, typically a pair of linked tapering rails that can be moved laterally to allow a train to pass from one line to the other.
  • Point Heater
    An electric heater to melt snow and ice that might otherwise impede correct operation of points
  • Point Motor
    A single or double solenoid device attached to a turnout so that the points may be operated electrically from a remote location
  • Points
    A junction of two railway lines that can be set to guide a train onto one of two alternative routes, or allow two lines to merge into one. Points can either be in "Reverse" or "Normal". Reverse being : The position of points where the reversed position indicates that the points are set for the(...)
  • Points Run Through
    A movement which runs through a trailing set of points which are not set in the correct position for the movement
  • POL
    Rail Plant Operating Company in Possessions Licence
  • POM
    Possession Optimisation Manager
  • PON
    Periodical Operating Notice: a bi-monthly publication, which contains all current amendments to the books of Rules and Regulations and certain miscellaneous notices.
  • Portal
    Entrance to a tunnel or a type of overhead line support
  • POS
    Plant Operating Scheme
  • POSE
    Person operating signalling equipment
  • Position Light Ground Signal
    Position Light Ground Signal
  • Possession
    When a section of track is required for maintenance and trains cannot run, it is handed over by the operators to the engineers, who take "possession". Special protective measures are used to prevent access by unauthorised trains. When the track is returned to the operators, the engineers "give(...)
  • Pot
    A ceramic stand that supports the conductor rail in DC areas.
  • Power Operated Points
    Points operated by means other than mechanical (eg electric motor, hydraulics or compressed air).
  • PPE
    Personal Protective Equipment
  • PPM
    Public Performance Measure
  • PPS
    Possession Planning System - it manages the process for booking and recording of national engineering and access requirements (possessions, worksites, temporary speed restrictions).
  • Propelling
    Moving a train using a locomotive at its rear
  • Protection
    In a specialised sense, used for the rules governing the protection given to a train, which stops in an unusual location or becomes derailed, to stop another train hitting it.
  • PSB
    Power signal box
  • PSLG
    Project Safety Leadership Group
  • PSR
    Permanent Speed Restriction
  • PTS
    Personal Track Safety- Competence certificate to enable as to correctly determine their responsibilities and duties when working ‘On or Near the Line’ on the Railway Infrastructure
  • Pull Off signal
    -Operate signal to give a proceed or a less restrictive indication.
  • Push Pull
    A method of locomotive-hauled train in which the locomotive is permanently attached at one end of the train and when at the rear is remotely controlled from a driver’s cab built into the leading vehicle (see DVT). Its advantage is that run-round moves or turnover locomotives are unnecessary.
  • PWay
    Permanent Way. The track of a railway line; the ballast, sleepers and rails.
  • q

  • Q Train
    Trains with British Transport Police on board to combat trespass and vandalism. Also applies to a pathway not always utilised (runs required, for example, a Sandite train).
  • Quadruple Track
    A railway route in which two sets of tracks are provided for each direction of travel.
  • r

  • RA
    Route Availability or Right Away platform indicator
  • RA Indicator
    A special signal to a train driver that a train is ready to depart from a station
  • RAIB
    Rail Accident Investigation Branch. The RAIB is the government railway accident investigation organization for the UK. It investigates railway accidents/ incidents on the UK’s railways involving train movements to improve safety, not to establish blame.
  • RAIB Accredited Agent
    An individual certificated by the RAIB (probably a Network Rail employee) who will assist in recording evidence at an incident site. May well be first RAIB representative to attend site.
  • Rake
    A complete set of (loco-hauled) coaches.
  • RAM
    Route Access Manager Route Asset Manager or Reliability Availability Maintainability Depends on context, can be either: Route Access Manager (e.g. buildings, OLE, P&D, Telecoms), Route Asset Manager, or Reliability Availability Maintainability (in connection with(...)
  • RCC
    Railway Contractors Certificate
  • RDG
    Rail Delivery Group
  • reactionary delay
    The delay to trains resulting from an earlier train delay.
  • Red Zone
    A site of work that is on or near the line, where the trains are still running
  • Red Zone Working
    A site of work if it is on or near the line and it has not been possible to set up a Green Zone
  • refuge
    A place of safety in tunnels and alongside high speed lines where employees can stand in safety; also A dead end siding allowing trains to be shunted off the running lines
  • Region
    Since 2019 Network Rail is geographically split into 5 Regions Scotlands Railway Southern Wales and Western Eastern North West and Central
  • regulate
    Signallers can regulate the train service by giving priority to one train over another.
  • Regulator
    Officer appointed by the Government to regulate the railway industry
  • relay
    An electro-mechanical switching device used in many types of signalling systems; it “relays” instructions to signals and points. Relays are now being superseded by Solid
  • relief line
    A secondary line which runs alongside a main line.
  • RETB
    Radio Electronic Token Block  is a system of railway signalling used in the United Kingdom. It is a development of the physical token system for controlling traffic on single lines. On arrival at a "token exchange point", the driver reports his/her position to the(...)
  • reversible line
    A track on which traffic may be worked in either direction (bi directional)
  • RFID
    Radio Frequency IDentification
  • RG
    Miniature red/green warning lights (at level crossing).
  • RIAG
    Rail Industry Assurance group
  • RIC
    Rail Incident Commander: strategic level overview of incident management.
    Reporting of Injuries, Diseases or Dangerous Occurrence Regulation- legislation guiding the reporting of injuries.
  • RIEF
    Rail Industry Environment Forum
  • Right of way
    A term used for the signal given by a guard to a driver that he is permitted to depart
  • Right side failure
    A mode of failure, which causes a piece of equipment to cease functioning without compromising the safety of trains.
  • RIO
    Rail Incident Officer: normally a Network Rail employee who takes control at the scene of a rail incident or accident. Works with Incident Officers from emergency services to co-ordinate the tasks at the scene.
  • RMD
    Route Managing Director
  • RME
    Rail Management Engineer
  • RMT
    Railway, Maritime and Transport Union
  • RO
    Rail Operator
  • Road
    Slang term for the track or a train pathway along the route
  • ROGS
    - Railways and Other Guided Transport Systems (Safety) Regulations
  • Rolling Stock
    Anything with wheels on it which can run on the track including locomotives, carriages, goods wagons, and maintenance vehicles.
  • rough ride
    A term used when a member of the train crew reports a “bumpy” ride at a given location
  • route
    area of operation within Network Operations
  • RPOS
    Responsible Person On Site
  • RRAP
    RRAP – Road Rail Access Point
  • RRV
    Road Rail Vehicle. A vehicle that can travel on the road under its own power and also travel on the rails by virtue of a rail wheel guidance system
  • RSC
    Return Screening Conductor
  • RSO
    Residual Switch Opening
  • RSSB
    Rail Safety and Standards Board
  • Rule Book
    A book, which incorporates most of the rules to be observed by general railway staff for the safe operation of the network. Published in Modules by the RSSB. Updated every June and December
  • rules of the route
    Rules agreed with train operators under which speed restrictions or temporary line closures can be imposed for maintenance purposes
  • run by
    Unauthorised passing of a signal at danger, or overshooting a station or designated stopping point.
  • run through
    A run-through is an unintended movement of a rail vehicle through a set of points in the trailing direction when the points are set against the movement being carried out.
  • Running Rail
    Running surface of the rail. Can also apply to an interchange point between road and rail.
  • s

  • S and C
    switches and crossings the specially machined rails designed to permit trains to transfer between tracks.
  • S and T
    Signalling and Telecom
  • sandite
    A mixture of sand and antifreeze, used for assisting traction adhesion during extreme weather. Sandite S4 also contains steel shot to assist track circuit operation
  • SATS
    Sectioning Auto-Transformer Site From Wikipedia: In UK railway applications, it is common to power the trains at 25 kV AC. To increase the distance between electricity supply Grid feeder points they can be arranged to supply a 25-0-25 kV supply with the third wire (opposite phase) out of reach(...)
  • SBI Gauge
    A loading gauge that permits operation of road-rail swap body vehicles
    Supervisory Control and Data Acquisition
  • Scotch
    A lump of wood either placed in an open switch of points to prevent movement, or on a rail under a wheel to prevent a vehicle from being moved.
  • SCWO
    Showing Clear When Occupied
  • Section
    A section of track protected by signals.
  • Semaphore Signals
    Signals usually worked mechanically by wire from a signal box’s lever frame, but can be electrically operated; these are mechanical arms rather than coloured lights
  • Sentinel
    Sentinel is the organisation set up to administer Track safety competence
  • Sequential Locking
    A refinement of ‘Interlocking’ that ensures signals are operated only in a certain order.
    Seasonal treatment on-Line. It’s a database that is used to manage the national seasonal infrastructure treatment plan
    Meaning of So Far As Is Reasonably Practicable (SFAIRP): A guideline for rail organisations to assist them in developing a decision making framework
    Safety, Health and Environmental Leadership Team
  • shoe
    Term used as a shortened version of "collector shoe" to denote a third rail current collection device mounted on the bogie of a direct current electric train.
  • shots
    A slang term for detonators
  • shunt
    This is a short distance stock movement for the purpose of re-positioning, re-marshalling or berthing of trains.
  • Siding
    A single piece of track attached to a mainline or headshunt at one end only. The other end will usually be terminated with a buffer stop so as to ensure that trains do not run off the end.
  • Signal
    Visual indication passed to a train driver to advise the speed, direction or route of the train. There are almost as many types of signals as there are railways but they fall into the following main categories:1) handsignals - used mainly where there are no fixed signals or where the fixed(...)
  • signal box
    The control centre for signalling trains. This is where the signallers control the movements of trains by signals.
  • signal gantry
    A framework suspended across several train tracks, and upon which many signals may be mounted
    Simplified Bi-Directional Signalling: signalling provided to allow trains to run in the “wrong” direction during engineering work, line blockages, etc. without resorting to pilotmen
  • SIP
    Safety Improvement Programme
  • SISS
    Station information and security systems - customer information screens etc. (also partly known as CIS
  • six foot
    Commonly used term to describe the space between two adjacent tracks
  • sleeper
    A beam spanning the track, which is used to support the rails. Originally wooden but concrete sleepers are generally used now. Steel sleepers have also been used occasionally
  • SLU
    Standard Length Unit: the measurement of the shortest wagon (21ft); used to describe the length of vehicles and loops so it is known if trains can be accommodated
  • SLW
    Single Line Working
    Signal Monitoring And Reporting to TRUST: provides information automatically on actual train running.
  • SPAD
    Signal Past at Danger. There are various degree and type of SPADs catergorised A-D
  • special
    A train that was not in the working timetable, and had been programmed via a special traffic notice
  • speed restriction
    A Blanket Emergency Speed restriction is one that is applied over a wide area in response to, for example, bad weather. Advice to drivers and signallers on when a blanket emergency speed restriction is imposed or withdrawn is via Operations Control. If the restriction is imposed for more than(...)
  • SPT
    Signal Post Telephone. A telephone located on or near a signal where the driver can directly communicate with the signaller. Also used for any other railway staff to contact the signal box.
  • Spur
    A piece of railway line which branches off from a main line. Can be used as an alternative route if there is an incident occuring on the main line
  • SSA
    Self Supporting Anchor (for OLE structures)
  • SSI
    Special Site Inspection or Investigation
  • SSO
    Special Stop Order. Passenger trains stopping additionally at stations.
  • SSoW or SSoWP
    Safe System of Work Planning/Pack - these are plans that are to ensure a safe system of work is in place before work starts
  • SSSI
    Site of Special Scientific Interest
  • STE
    Safety, Technical Engineering directorate within Network Rail- replaced with the Technical Authority (TA) in 2020
  • Stoneblower
    A machine developed to maintain the trackbed.
  • Stressing
    The process of stretching continuously welded rail so that the stress-free temperature of the rails is within the required so that the stress-free temperature of the rails is within the required range (21–27°C).
  • Structure
    A construction such as a bridge (rail, road, foot or equestrian), viaduct, retaining wall, tunnel or similar, signal or electrification post or gantry, station construction such as a platform wall, track drainage manhole or cable pit, and any other construction on Network Rail Controlled(...)
  • Substation
    A building or compound containing electrical switchgear and equipment which supplies electricity to the conductor rails.
  • Swing Nose Crossing
    A point in which the flangeway at the nose is arranged to open or close according to which way the points are set, to provide a smooth passage for the train wheel.
  • switch rail
    The moving portion of rail on each side of a set of points.
  • SWL
    Safe Work Leader - person accountable for safe delivery of work within a worksite
  • SWM
    Safe Work Manager
  • SWMP
    Site Waste Management Plans Regulations 2008 require that any person intending to carry out a construction project in England with an estimated cost of greater than £300,000 must prepare a site waste management plan – an ‘SWMP’. This must be updated in accordance with the Regulations, with(...)
  • t

  • T and V
    Tresspass & Vandalism. Now called Railway Crime
  • TA
    within the railway TA is Technical Authority- a directorate of Network Rail
  • TAC
    Train Arrived Complete - The authorised memeber of traincrew will operate the Train Arrived Complete switch located on the platform on which a train has arrived complete with tail lamp, under absolute block signalling when the train has not passed the signal box for the signaller to observe(...)
  • Tamper
    A permanent-way maintenance machine, consisting of a number of vibrating rods, which, when dug into the ballast, cause the ballast material to pack more firmly under the track
  • Tamping
    Process that compacts ballast under sleepers to maintain the correct geometry of the track.
  • TASS
    Tilt Authorisation and Speed Supervision system - to authorise tilting operation only on tilt cleared routes and to prevent the line speed being exceeded when these trains are operating in tilting mode.
  • TBS
    Task Briefing Sheet
  • TCB
    Track Circuit Block- A modification of the Absolute Block System, employing track circuiting throughout. A train may proceed, as soon as the line is clear, to the next stop signal plus the required overlap beyond that signal
  • TCMI
    Tunnel Condition Marking Index
  • TCOD
    Track Circuit Operating Device. Used to activate track circuits so that they show occupied
  • TCS
    Train Control System
  • Ten Foot
    Identifies the term given to the central space on a four-track railway (may actually be less than six feet).
  • Terminus
    A station found at the end of a railway line where departing trains have to travel back in same direction out of the platforms as that from which they arrived
  • Theatre lights
    Directional lights found on approach to major stations
  • Third rail
    A system of railway electrification in which the traction current is picked up by a skate or shoe which makes contact with a third rail located between or to one side of the running rails, and returned via both or either of the two running rails.
  • Three aspect signal
    A colour-light signal capable of displaying three aspects.From top to bottom the lights are green, yellow, and red. A red indication means that the next section contains a train. A yellow indication means that the next section is clear but there is a train in the following one. A green(...)
  • TLP
    Thameslink Programme
  • TMD
    Traction Maintenance Depot
  • TNC
    Temporary Non Conformance /Compliance
  • TOC
    Train Operating Company
  • TOPS
    Total Operations Processing System: a prime source of train operation data such as destination, load and location. TOPS provide a comprehensive system for monitoring a train’s complete movement cycle from workshop and maintenance
  • TOWS
    Train Operating Warning System: gives audible warning to those working on the track of the approach of the train
  • TPAT
    Take Possession Around Train.  At the start of a possession, an engineering train or on-track-machine may be moved into position, before any worksites are set up. The term for this is Take Possession Around Train.
  • TPWS
    Two sets of two electronic loops are set in the track before signals where a SPAD would be most likely to put a train into risk of being involved in a collision. The loops are energised when the signal is red and emit electromagnetic fields. When an antenna on the train detects the field(...)
  • Track Circuit
    An electrical circuit that includes an insulated section of track. A train occupying the track will complete the circuit by connecting the two rails together via its wheels and axles thus signaling the trains occupation of that section of track. Track circuits are designed to detect the(...)
    Track Renewal and Maintenance Machine
  • TRB
    Train Register Book
  • Treadle
    Electrical switch operated by the train wheels, often for level crossing approach.
  • TRTS
    Train Ready To Start "Train Ready To Start". The platform staff (or driver, when in a siding) will operate the Train Ready To Start switch, located on the platform (or siding) when the train is ready to depart for its journey
  • Trust
    Train Running System (TOPS - Total Operations Processing System): computer system, which records details of train operational data as compared with schedule, supporting the logging of delays and associated attribution process.
  • Trust DA
    The delay attribution system for recording the size and reason for delays recorded by TRUST.
  • TSA
    Track Safety Alliance
  • TSI
    Technical Specifications for Interoperability The development of Technical Specifications for Interoperability (TSIs) are the responsibility of the European Railway Agency (ERA).
  • TSR
    Temporary Speed Restriction
  • TSS
    Train Stop Sensor which is located immediately on the approach side of a signal and will activate if a train passes it when signal is at danger
  • TSSA
    Transport Salaried Staff Association union
  • TTC
    Twin Track Cantilever - a form of OLE structure with one post and carrying two sets of catenary from one cantilevered boom
  • TUPE
    Transfer of Undertakings (Protection of Employment) Regulations 1981; legislation that protects earnings and conditions when employees transfer from one employer to another
  • Turnout
    The track configuration enabling trains to change from one track to another (widely called Points).
  • TVP
    Track Visitors Permit- permit to allow temporary accompanied access to work site.
  • Two aspect signal
    A colour-light signal capable of displaying two aspects.
  • u

  • UFL
    Up Fast Line
  • UFN
    Until Further Notice
  • Up line
    That line on a multi-track main line where the direction of travel is towards London or designated location
  • UPS
    Uninterrupted Power Supply
  • USL
    Up Slow Line
  • UTX
    Under-Track Crossing – a conduit to carry cables, etc. from one side of the line to another
  • UWC
    User Worker Crossing
  • v

  • VCB
     'Vacuum Circuit Breaker' (VCB)  VCB cuts off the power from the OLE to the train
  • Vectorisation
    A manipulation of maps so they can be shown accurately on computer systems.
  • Vestibule
    The area at the end of corridor and saloon coaches, from which access may be gained to the side corridor or central passageway, outside doors, W.C. (if any), and corridor connection to the next coach (if any).
  • Viaduct
    railway structure which is used to carry railway tracks above the general level of the ground and is usually made up of a continuous series of bridges or trestles
  • Voiding
    The creation of a space below a sleeper, timber or bearer because of the displacement of the supporting ballast
  • VSTP
    Very Short Term Plan: the processing of track access bids received by Operational Planning up to two days before possession
  • VT
    Voltage Transformer
  • VTS
    Vehicle Tracking System
  • w

  • wagon
    a goods vehicle with no roof
  • WAR
    Work As Required; a method of working mainly used by train crews for flexibility
  • WARA
    Work Activity Risk Assessment
  • WEN
    Weekly Engineering Notice: contains details of the engineering work for the forthcoming week that train crews or others may require
  • Wet Bed
    Deterioration of sleepers and ballast caused by saturation
  • Wet Patch
    Also known as a "wet bed" this is a section of track where the ballast/sleepers become saturated through water contamination/leakage from either above or underground often resulting in a slight dip or reported "rough rides" in the track as trains pass over. Requires P/Way attention.
  • wheelchex
    A system to measure the forces generated by a train running on track.
  • whistleboard
    A lineside board, which indicates to Train Drivers where they are required to sound a warning
  • wideway
    -An area of the track bed which is off the end of a platform
  • WILD
    Wheel Impact Load Detector: device that measures the force exerted on the rail by each wheel of a train as it passes, and activates an alarm if any is excessive.
  • WON
    Weekly Operating Notice: contains the engineering work for the forthcoming week and any other information train crews may require.
  • WPP
    Work Package Plan
  • WSF/ Wrong Side Failure
    (i) Wrong Side Failure: something which fails in an unsafe condition (ii) Wrong Side Signalling Failure.  A wrong side failure occurs when equipment or a system does not fail safe. In other words, a failure occurs which could lead to an accident
  • WTT
    Working Timetable -A timetable used by railway operators, which includes the times of all regularly run trains (not just passenger trains).
  • z

  • zero plated
    A round plate with a “0” on it, which is located on a defective signal, that is showing a red aspect. Indicating that the Driver must contact the Signaller immediately on approach to the defective signal.

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