The MMPA Jargon Buster Page

Railway jargon and the multitude of abbreviations used by government departments and the railway industry can be very confusing to the uniniated. This page will attempt to unravel some of the mysteries. If you come across a word, phrase or abbreviation on this site, or on our local trains and stations, which you don't understand please inform your webmaster who will be pleased to add it to this page. He might even be prevailed upon to reword the offending page to make it more intelligible!

Words in yellow are defined elsewhere in the glossary.

This glossary does not include enthusiast slang which you can find (amongst other definitions) in dreadful.org.uk’s Jargon Buster.

See also Roger Ford’s Topical Railway Acronym Converter.

Go to: A B C D E F G H I L M N O P R S T U W Y

ACoRP

Association of Community Rail Partnerships

AHB

Automatic Half-Barrier - type of level crossing with barriers across half the width of the roadway on each side which are activated automatically by the approaching train. The crossings at Furze Platt and Cookham are AHBs (see Gallery 1, picture 10).

Airtrack

Now abandoned scheme by BAA to link Heathrow Airport via South-Western metals to Reading and Waterloo.

AOCL

Automatic Open Crossing, Locally controlled - type of level crossing without barriers or gates and with traffic signals operated by the approaching train. The crossings near Bourne End Marina on the Marlow line were AOCLs but have now been converted to AHB.

APRS

Assisted Passenger Reservation System

Arr or a.

Arrival Time

ARS

Automatic Routesetting System - normally an integral part of IECC but can be used with NX panels.

ASR

All Signals Red - panic button on a signalling panel.

ATO

Automatic Train Operation

ATOC

Association of Train Operating Companies (web site)

Avantix

(Avantix Mobile) Type of portable ticket issuing machine used on branch trains.

AWS

Automatic Warning System - indicates to the train driver by means of a "sunflower" display and either a bell or a hooter (or electronic equivalent) whether the signal he is approaching is showing a clear or a restrictive aspect. It automatically applies the brakes if the hooter warning is not acknowledged. The danger is that if a driver is used to running on single yellow or double yellow signals he could acknowledge the hooter by force of habit and carry on even if the signal is at danger. This is believed to have been the cause of the Ladbroke Grove mishap. The newer TPWS aims to overcome this drawback.

BAA

British Airports Authority - which owns the tracks between Hayes & Harlington and the Heathrow terminals.

Banner Repeater

You may see these above a platform or elsewhere on the railway where visibility of a signal is impeded. It consists of a white illuminated disc (usually LED or fibre optic these days) with a black (dark) horizontal or diagonal bar across it. If the bar is horizontal it indicates to the driver that the next signal is at danger.

BCR

Benefit Cost Ratio

Bo-Bo

Axle configuration of a locomotive with two bogies each having two wheelsets which are individually powered.

BRBR

British Railways Board (Residiary) Ltd.

Car

Carriage. You may see a sign board on the platform bearing a number and the words " Car Stop". This indicates where the front of a train of that length should stop. A letter "S" applies to all trains.

C-C

Axle configuration of a locomotive with two bogies each having three wheelsets which are geared together.

CBI

Computer Based Interlocking.

CCTV

Closed Circuit Television - used to monitor some level crossings, and for surveillance.

Chord

Short curve (actually an arc, not a chord) joining two intersecting railway lines.

CIS

Customer Information Systems

Class (1)

Locomotives and multiple units of a particular design are assigned to a "class" in NR's computer system. The first two or three digits of the fleet number indicate the class - two digits for locomotives and three for multiple units. Those you are likely to see in our area are:
37 - English Electric classic diesel-electric locomotive. These are slowly being replaced by more modern machines.
43 - HST power cars. Western Region HSTs were originally Class 253 but the power cars are now classed as locomotives because they got swapped around so much owing to failures that it became impossible to keep sets together in their original formations. Class 43 was originally used for “Warship“ class diesel-hydraulic locomotives.;
52 - “Western” class preserved C-C diesel-hydraulic locomotives. D1015 Western Champion is based at Old Oak Common depôt;
57 - re-engined Brush classic diesel-electric locomotives (formerly class 47) still used on the Night Riviera sleeper service.
59, 66 - General Motors diesel-electric freight locomotives;
60 - Brush diesel-electric heavy freight locomotive;
67 - Diesel-electric Bo-Bo 125mph mixed traffic locomotive as used on some Chiltern trains.
97 - Departmental (i.e. NR) version of the Class 37;
1xx - diesel-mechanical and diesel-hydraulic multiple units:
165 - Networker Turbo 2- or 3-car diesel multiple units used on local services;
166 - as 165 but 3-car units with air conditioning;
168 - Chiltern Railways "Clubman" DMUs;
172 - Diesel-mechanical multiple unit soon to be seen on Chiltern Railways and currently in use on the Gospel Oak - Barking line.
180 - Adelante 5-car 125mph DMU.
2xx - diesel-electric multiple units (DEMUs):
220 - Voyager DEMUs used on Cross Country services;
3xx - 25kV AC overhead and dual voltage electric multiple units (EMUs):
332 - Heathrow Express EMUs;
360 - Heathrow Connect EMUs;
4xx, 5xx - 750V DC third rail EMUs:
444, 450 - Siemens Desiro EMUs as used on SWT services into Reading.

Class (2)

Trains are classified according to the type of service. The classes are broadly as follows:
1. Express passenger train.
2. Ordinary passenger train, breakdown train or OLE train.
3. Freight train which can run at more than 75mph, or parcels train.
4. Freight train limited to 75mph
5. ECS train.
6. Freight train limited to 60mph
7. Freight train limited to 45mph
8. Freight train limited to or timed to run at not more than 35mph
9. Eurostar train
0. Lignt locomotive.
The train class is the first digit of the reporting number.

Class (3)

Standard of passenger accommodation (first class and standard class).

Clock Face

Phrase often used to mean regular departures at the same minutes past each hour.

CLRL

Cross London Rail Link - the organisation responsible for delivering Crossrail.

Co-Co

Axle configuration of a locomotive with two bogies each having three wheelsets which are individually powered.

CP

Control Period - a five year period used for railway planning. We are now in CP4 which runs from 1st April 2009 to 31st March 2014. CP5 runs from 2014 to 2019 and so on.

Crossrail

Scheme to connect lines east and west of London with a tunnel from Royal Oak to Pudding Mill Lane (for Shenfield) and Victoria Dock (for Abbey Wood). In the west trains will terminate at Heathrow, West Drayton and Maidenhead, with the route through to Reading protected for future use. stations (web site).

CRPB

Chiltern Railways Passenger Board

CRS

Computer Reservation System. CRS Codes are the three character station codes used by the online booking and reservation system. You can enter the CRS code instead of the full station name on the National Rail journey planner.

CSR

Cab Secure Radio

CTRL

Channel Tunnel Rail Link

Darwin

ATOC’s computer system for handling service disruption data across the network. This will eventually interface with all the operators’ CIS.

DB

Deutsche bahn - German Railways, parent company of Chiltern Railways, Arriva, DBS.

DBS

Deutsche Bahn-Schenker freight company that bought out EWS.

DEMU

Diesel-Electric Multiple Unit (with one or more diesel generators and electric traction motors).

Dep or d.

Departure Time

DfT

Department for Transport - government department.

DfT Rail

Part of the DfT responsible for railways. It replaced the Strategic Rail Authority (web site).

Diagram

This refers to the timetable for a particular train and/or train crew. It consists of a number of journeys usually starting and finishing at a depôt or other stabling point. The word comes from the graphical representation of the timetable with time along the X-axis and distance on the Y-axis.

DLR

Docklands Light Railway

DMU

Diesel Multiple Unit train, e.g. the Class 165 Turbo used by FGW and Chiltern Railways on suburban services.

DOO

Driver Only Operation

DOR

Directly Operated Railways - Government owned company which can take over failed franchises until they are re-let (e.g. East Coast).

Down or DN

Direction of travel for trains heading away from London (or other major centre).

DTL

Diesel Trains Limited

DVT

Driving Van Trailer - an unpowered vehicle with a driving cab and guard's van or luggage space. It is used at the opposite end of a push-pull train from the locomotive in order to drive the train when the locomotive is propelling it from the rear.

Dwell Time

The length of time the train takes for a station stop.

ECS

Empty Coaching Stock - i.e. an empty train running to or from a depôt or stabling point or between service journeys.

EMU

Electric Multiple Unit

Engine

A component of a locomotive or power car or DMU which generates power. Except in the case of steam engines, an engine is not a locomotive or vice-versa!

EROS

Emergency Restriction of Speed

ERTMS

European Railway Train Management System - a moving block signalling system using in-cab displays instead of trackside signals that is currently being implemented on the Cambrian Line.

ETCS

European Train Control System

Eurostar

Brand name for services between London and Brussels or Paris via the Channel Tunnel (web site).

EWS

English Welsh and Scottish Railway - freight operator, now DB Schenker (DBS).

Feather

A row of five white (strictly speaking, lunar) lights on top of a signal head to show when a diverging route is set. The first feather is at 45° to the vertical on the appropriate side, and additional feathers may be added at 90° and 135°.

FGW

First Great Western - part of First Group plc and holder of the train operating franchise for our line.

Flying Scotsman

LNER A3 pacific locomotive no. 4472.

Flying Scotsman, The

Named train which runs between London King's Cross and Edinburgh.

FOC

Freight Operating Company

Four foot

The gap between the rails (actually 4' 8½")

FPL

Facing Point Lock - to prevent the points moving under a passing train at a diverging junction.

GLA

Greater London Authority

GRIP

Guide to Railway Investment Projects - Network Rail’s management and control process for enhancements. more information

Ground Frame

A signal lever frame mounted on the ground usually in the open but can be covered or inside a hut (see Gallery 1).

GWML

Great Western Main Line

Headcode

A code displayed on the front of a train. In most areas this was the train's reporting number and may still be displayed on some freight locomotives. On the former Southern Region, two character headcodes are used to indicate the route but are not used on some types of train.

Headway

The minimum time between consecutive trains on a particular line.

HEx

Heathrow Express - the fast service between Paddington and Heathrow Airport.

HLOS

High Level Output Specification - sets the outputs that the government wished to purchase from the railway industry during a Control Period (CP).

HS1

High Speed One - high speed line between London St. Pancras and the Channel Tunnel, formerly CTRL.

HS2

High Speed Two - proposed high speed line connecting London with the Midlands and the North.

HSS

High Speed Services - FGW name for services operated by HSTs.

HST

High Speed Train, also known as the InterCity 125 and used on FGW's long distance services.

ICC

Integrated Control Centre - see foll.

IECC

Integrated Electronic Control Centre - our area is controlled by the IECC at Slough Signalling Centre.

IEP

Intercity Express Programme - programme to design and build a replacement for the HST

IIP

Initial Industry Plan - first step in deciding what can be provided in the HLOS for the next CP.

Interlocking

Part of the signalling system which ensures the safety of the railway. It ensures that a route cannot be set if it conflicts with another route that has aready been set or if the section ahead is occupied. It also ensures that a signal cannot be cleared until a route has been set (i.e. the points set and proved for the intended course) and the section ahead is unoccupied. Interlocking can be achieved by means of a mechanical system of bars and levers or by means of electrical relays or solid state (computer based) systems.

ITPS

Integrated Train Planning System - new NR timetable planning system.

ITSO

Integrated Transport Smartcard Organisation - body formed to draw up standard specifications for interoperable smartcard based ticketing systems similar to (but not including) Oyster.

LCD

Liquid Crystal Display - used for flat screen displays in PIS.

LED

Light Emitting Diode - used in modern signalling and PIS.

LENNON

Latest Earnings Networked Nationally Over Night - ticket sales database.

Light Locomotive

A locomotive running on its own, without a train.

Loading Gauge

Outline or profile which is not exceeded by any part of the train. There is a series of standard loading gauges which apply to different types of train. The term is also applied to a device comprising an arc suspended over the line at the exit of a goods yard, colliery, quarry, etc. to check that wagons have not been overloaded.

Locomotive

A motive power unit used to haul and/or propel a train. A locomotive is not a train. Flying Scotsman is a locomotive: The Flying Scotsman is a named train.

Loop

A side track used to accommodate a slow freight train so that a faster train can overtake it. Passenger trains are not normally ‘looped’, charters excepted.

LOROL

London Overground Rail Operations Limited

LTV

London and Thames Valley

LUL

London Underground Limited

MAA

Moving Annual Average - usually an average of the last 12 monthly figures which is updated every month.

Main Lines

In the local context, the fast lines between London and the West of England which are on the south side of the railway between Didcot Parkway and Paddington. Also used in a more general sense to mean not the branch lines.

MAS

Multiple Aspect Signalling - i.e. colour light signalling with separate lenses on the signal head (cf. searchlight signal).

MBWG

Marlow Branch Working Group, comprising MMPA, Bucks County Council, FGW, NR, Wycombe District Council, Marlow Town Council and RBWM

MCB

Manually Conterolled Barrier (level crossing)

MMPA

Marlow-Maidenhead Passengers' Association - action group representing public transport users.

MOIRA

Industry standard timetable based passenger demand forecasting model. It is a girl’s name, not an acronym.

MRL

Mendip Rail Limited - company that operates stone trains on behalf of Foster Yeoman and Hanson (formerly ARC).

Multiple Unit

A set of coaches which is semi-permanently coupled (or a single railcar) and which has a driving cab at each end. It is called a multiple unit because it can work in multiple with other units of the same type with the whole train being controlled by a driver in the leading cab. Some locomotives can also work in multiple (cf. tandem).

National Rail

An umbrella description used by ATOC to provide travel enquiry and booking services. It is also used as a generic name for heavy rail services as distinct from light rail, Underground and Metro services. National Rail Enquiries

Networker

Series of DMUs and EMUs of Classes 165, 166, 365 and 465 introduced by Network SouthEast.

NLRIP

North London Route Improvement Plan

NR

Network Rail - the company which owns the railway infrastructure and signalling, and which operates principal stations such as London Paddington.

NRE

National Rail Enquiries - enquiry and journey planning service run by ATOC.

NSIP

National Station Improvement Scheme

NX

Entrance-Exit - type of signalling control panel on which the signaller sets a route by first pushing the button at the start (entrance) of the route, and then the button at the end (exit) of the route.

Occupation crossing

A level crossing provided for the use of owners of adjacent property (typically farms). The crossing has gates across the roadway but no traffic signals. There is usually a telephone for contacting the signalman if vehicles or animals have to be taken across the line.

Off

State of a signal which is not at danger (cf On). You may see an illuminated OFF box on a station platform. It indicates to platform staff and train crew that the starting signal is off. If the line is reversible the OFF box will also indicate for which direction (up or down) the signal is off.

OLE

Overhead Line Equipment (for electric traction)

On

State of a signal at danger i.e. red (cf Off).

OOC

Old Oak Common - proposed site for HS2 interchange with Crossrail.

Open Access

An Open Access operator is one which operates a train service on a purely commercial basis without government subsidy and not within a government awarded franchise (e.g. Grand Central, Hull Trains).

ORCATS

Operational Research Computerised Allocation of Tickets to Services - rail industry income allocation model.

ORR

Office of Rail Regulation

OTDR, OTMR

On Train Data (or Monitoring) Recorder - railway equivalent of the “black box”

Overground

Brand name for surface rail services operated by LOROL on behalf of TfL.

Oyster

Smartcard payment system used by TfL and being extended to National Rail services within the GLA area.

Passenger Focus

National rail consumer watchdog. (web site).

PiXC

Passengers in Excess of Capacity

PIS

Passenger Information System, also known as CIS.

Possession

A stretch of line handed over to engineering departments for maintenance and not available for use by trains other than engineer's trains and special vehicles needed for the work.

Power Car

Although similar to a locomotive, a power car is designed to be used as part of a fixed formation train and may include a guard's van. A power car has a driving cab at one end only although it may have basic controls at the other end for use when shunting in a depôt. An HST has a power car at each end.

PPI

Point Position Indicator (like a signal but only to indicate which route is set).

PPM

Public Performance Measure - a hash-up of punctuality and reliability figures expressed as a percentage.

PSR

Passenger Service Requirement - the minimum level of service required of a franchise.

PTA, PTE

Passenger Transport Authority / Executive

PW

Permanent Way - the railway track itself, and the track bed.

RA (1)

Right Away - signal to driver to start. You may see an illuminated RA box at the end of the platform.

RA (2)

Route Availability - a number from 1 to 10 which indicates what motive power units can use what routes, which depends mainly on axle loadings and overall weight. A locomotive may not use a route with a lower RA number than its own except with special dispensation and possible speed restrictions.

RAIB

Rail Accident Investigation Branch. The aim of the RAIB is to investigate accidents, infringements and near misses, and to make recommendations to avoid a recurrence, without attaching blame.

RBWM

Royal Borough of Windsor and Maidenhead

Relief Lines

In the context of the Great Western lines, the relief lines are the slow lines between Didcot Parkway and London, comprising the two passenger tracks on the north side of the railway.

Reporting Number

A four-character code used to identify a train in the signalling system and in the WTT. The first digit is the train's Class (2). The second is a letter indicating the destination and is followed by two digits which indicate the particular train on that route. (further information)

Reversed

Points are said to be reversed when set away from the normal (usually straight ahead) route.

RHTT

Rail Head Treatment Train - to deal with leaves on the line.

Road

The railway track. A train “has the road” when it has a route set ahead of it and the signal is off.

Rolling Stock

General name for railway vehicles including locomotives, coaches and wagons.

RoSCo

Rolling Stock Company - which leases trains to the TOCs.

RPC

Rail Passengers' Council - now superseded by Passenger Focus.

RRI

Route Relay Interlocking - type of interlocking using electrical relays.

RSPG

Railway Safety Principles and Guidance

RSSB

Rail Safety and Standards Board

RUS

Route Utilisation Strategy - study (by NR and previously, SRA) to determine how best the maximum capacity can be delivered by the railway with its existing assets and with the funds that are likely to become available.

S & C

Switches and Crossings - pointwork on the track. Also the Settle & Carlisle line.

S & T

Signals and Telecommunication

SDO

Selective Door Opening

Searchlight Signal

A signal head which is capable of showing different colours through a single lens and lamp unit, using an electro-mechanical filter arrangement. Modern LED signals do a similar job without the need for filters. See also MAS.

Set

A set of coaches or a multiple unit.

SFN

Strategic Freight Network

SISS

Station Information and Surveillance Systems

Six foot

The gap between two adjacent tracks (cf. four foot).

SLC

Service Level Commitment - service evels that a TOC is committed to provide under a franchise.

SLW

Single Line Working

SoFA

Statement of Funds Available

SPAD

Signal Passed At Danger

SPATE

Speed Previously Announced Terminated Early i.e. a TSR that has been lifted earlier than planned.

SRA

Strategic Rail Authority - now superseded by DfT Rail

SPT

Signal Post Telephone

SSI

Solid State Interlocking

STANOX

Station Number Code used within TOPS to indicate a particular piece of railway (siding, station, depot, etc.).

SWT

South West Trains - TOC operating services out of London Waterloo.

Tamper

A permanent way machine used to pack the ballast evenly underneath the track.

Tandem

Two or more locomotives are said to be working in tandem when they coupled together and both/all working but with a driver in each locomotive (cf. multiple).

TfL

Transport for London - transport authority for Greater London reporting to the Mayor of London.

TIPLOC

Timing Point Location - a unique six-character code allocated to each point used for timetabling purposes.

TMD

Traction Maintenance Depot

TOC

Train Operating Company - company which holds a franchise to operate passenger rail services.

Token

An object (either physical or electronic) which permits a driver to enter a single line section. On the Marlow line there are token sections between Maidenhead and Bourne End, and between Bourne End and Marlow. The tokens are in the form or large keys which are held in token instruments (see Gallery 1) at Maidenhead and Bourne End. Only one may be removed from the system at any one time, thus preventing two trains colliding on the single line.

Top & Tail

To couple a locomotive at each end of a train to permit reversal where it is not possible or not desirable to run round.

TOPS

Total Operations Processing System - computer system used by Network Rail to keep track of all rolling stock, motive power units, train consists, etc.

TPH

Trains Per Hour

TPWS

Train Protection and Warning System - this supplements AWS and has the added capability to prevent trains passing signals at danger. It is effective for train speeds up to 75mph.

Track Circuit

Electrical circuit through the running rails which is either completed or shorted out by the wheelsets of any railway vehicle occupying that section of track.

Train

You probably know what a train is, but for the benefit of any hacks reading this, a locomotive is not a train!

TRTS

Train Ready To Start - you may see a TRTS plunger on the platform at major stations. It is used by the platform supervisor to indicate to the signalling system that the train is ready to depart. See also RA (1).

TSR

Temporary Speed Restriction

TT

Timetable

Turbo

Originally “Networker Turbo” or “Thames Turbo” - the name given by Thames Trains to the Class 165 and 166 diesel trains which work our local services. The Class 166 units are the ones with air conditioning (which may or may not work). These are the diesel versions of the Networker series of trains introduced by Network SouthEast in the 1980s.

TV

Thames Valley

TVSC

Thames Valley Signalling Centre (at Didcot)

TWA

Transport and Works Act

UIC

Union Internationale des Chemins de Fer (International Union of Railways).

Unit

See Multiple Unit.

Up

Direction of travel of trains heading towards London (or other major centres). For cross-country routes it can be arbitrary.

W

Whistle. You will usually see a “W” sign by the line when approaching a level crossing (except for crossings with full barriers and CCTV supervision).

WHIRS

Wider Heathrow Integrated Rail Strategy

WSMR

Wrexham, Shropshire and Marylebone Railway Company. Open access operator which ceased operating on 28th January 2011.

WTT

Working Timetable - the timetable used by train crews and signallers. It shows times to a precision of half a minute and may differ slightly from the public timetable. It shows times at points other than station stops (e.g. passing times at junctions or stations where the train does not stop - see TIPLOC) and it includes scheduled trains other than passenger trains in service.

Yellow

Railway signals have yellow aspects, not amber!