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The MMPA Jargon Buster Page

Glossary of Railway Jargon and Abbreviations

Railway jargon and the multitude of abbreviations used by government departments and the railway industry can be very confusing to the uninitiated. 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!

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.

Words and abbreviations in yellow are defined elsewhere in the glossary.

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

Click on the index letter to return to the top.

A

ABCL
Automatic Barrier Crossing, Locally controlled.
AC
Alternating Current - for traction usually supplied at 25kV, 50Hz by OLE.
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.
ANPR
Automatic Number Plate Recognition
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 ABCL.
APCOA
Company that operates car parks on behalf of GWR and Chiltern, amongst others.
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 (aka “Stop All Trains”).
ATCO
Association of Transport Coordinating Officers.
ATO
Automatic Train Operation
ATOC
Association of Train Operating Companies, now absorbed into RDG
Avantix
(Avantix Mobile) Type of portable ticket issuing machine formerly used on branch trains.
AWB
Advance Warning Board
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.

B

BAA
British Airports Authority - former owner of the three London Airports. Heathrow Airport Limited now owns Heathrow Airport including the railway between Heathrow Airport Junction (west of Hayes & Harlington) and the Heathrow terminals.
Ballast
The material, typically granite, under the track that supports the sleepers.
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 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. Modern versions use fibre optic displays or LEDs, sometimes with a green background if the signal is off.
BCR
Benefit to Cost Ratio
Bi-mode
describes a train that can use both electric and diesel traction.
Bo-Bo
Axle configuration of a locomotive with two bogies each having two wheelsets which are individually powered.
BRBR
British Railways Board (Residiary) Ltd.

C

Cant
A measure of the height that one rail of a track is above the other.
Cant Rail
The line where the roof of a carriage meets the body side. Cant rail lights are the amber lights on the outside of the coach that indicate that one or more of the doors is unsecured.
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.
CBTC
Communications Based Train Control.
CCTV
Closed Circuit Television - used to monitor some level crossings, and for surveillance.
CD
Close Doors (signal to driver)
Cess
The area on either side of the railway, outside the running rails.
CET
Controlled Emission Toilet (i.e. with retention tank).
Chord
Short curve (actually an arc, not a chord) joining two intersecting railway lines.
CIL
Community Infrastructure Levy - paid by developers (replaces section 106 payments).
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.
57 - re-engined Brush classic diesel-electric locomotives (formerly class 47) still used on the Night Riviera sleeper (2) service.
59, 66 - General Motors diesel-electric freight locomotives;
60 - Brush diesel-electric heavy freight locomotives;
67 - Diesel-electric Bo-Bo 125mph mixed traffic locomotives previously used on some Chiltern trains.
68 - New Vossloh diesel-electric mixed traffic locomotives six of which have been subleased by Chiltern Railways to replace the Class 67s.
70 - General Electric heavy haul freight locomotives.
97 - Departmental (i.e. NR) version of the Class 37;
1xx - diesel-mechanical and diesel-hydraulic multiple units:
150 - Sprinter 3-car diesel units unsed on the Reading-Basingstoke route on weekdays;
165 - Networker Turbo 2- or 3-car diesel multiple units used on local services;
166 - Networker Express 3-car diesel multiple units with air conditioning and first class accommodation;
168 - Chiltern Railways "Clubman" DMUs;
170 - Bombardier Turbostar multiple unit used by Chiltern Railways amongst others;
172 - Diesel-mechanical multiple unit now in use on Chiltern Railways inner suburban services.
180 - Adelante 5-car 125mph DMU.
2xx - diesel-electric multiple units (DEMUs):
220 - Voyager DEMUs used on Cross Country services;
230 - VivaRail prototype DEMU based on District Line D78 stock.
3xx - 25kV AC overhead and dual voltage electric multiple units (EMUs):
332 - Heathrow Express EMUs;
345 - new Crossrail trains (25kV AC).
360 - Heathrow Connect EMUs;
387 - Bombardier Electrostar units now entering service with GWR.
4xx, 5xx - 750V DC third rail EMUs:
444, 450 - Siemens Desiro EMUs sometimes seen on SWR services into Reading.
458 - Alstom Juniper EMUs used on SWR services into Reading.
700 - new Thameslink trains (25kV AC and 750V DC).
707 - New Siemens trains for SWR (750v DC).
800 - new bi-mode IETs (25kV AC and diesel).
801 - new electric IETs (25kV AC). Current orders have been switched to Class 800.
802 - new Hitachi bi-mode trains similar to Class 800 but ordered by GWR for services in the South-West.
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, or ECS train on its way to form a service.
4. Freight train limited to 75mph
5. ECS train returning to depot or stabling point, or lower priority than class 3.
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. Light 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
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 CP5 which runs from 1st April 2014 to 31st March 2019. CP6 runs from 2019 to 2024 and so on.
CRL
Crossrail Limited
Crossrail
Project 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, Maidenhead or Reading. (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 - now being replaced by GSM-R.
CTRL
Channel Tunnel Rail Link (now HS1)

D

DAA
Disability Access Act, now replaced by the Equality Act.
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.
DBC
Deutsche Bahn Cargo - new name for DBS freight operations in the UK.
DBS
Deutsche Bahn-Schenker freight company that bought out EWS, now DB Cargo.
DC
Direct Current - traction current is normally 750V supplied by third rail on NR lines and at 660V by third and fourth rails (+440V outside rail, -220V centre rail) on LUL.
DCI
Driver’s Crossing Indicator - flashing red light that changes to flashing white light when the barriers are down and the road is closed to traffic.
DCO
Driver Controlled Operation - where the driver is responsible for releasing and closing the doors, but there is normally another member of staff on board to look after passengers, check tickets, etc.
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. Turbo used by GWR and Chiltern Railways on suburban services.
DOO
Driver Only Operation. On the Marlow branch DOO is only permitted between Maidenhead and Bourne End.
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).
DPTAC
Disabled Persons Transport Advisory Committee
DTL
Diesel Trains Limited
DVD
Driver’s Vigilance Device
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 a train is stationary at a station.

E

ECAM
Enhancement Cost Adjustment Mechanism - ORR review process to determine value for money.
ECS
Empty Coaching Stock - i.e. an empty train running to or from a depôt or stabling point or between service journeys.
EDL
Electro-Diesel Locomotive - an electric locomotive with a diesel engine for operation on non-electrified lines.
Elizabeth Line
Brand name for Crossrail 1 (East-West) services.
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 fixed or moving block signalling system (there are three levels) using in-cab displays instead of trackside signals that is currently 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 Cargo (DBC).

F

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 former holder of the train operating franchise for our line. Now replaced by GWR.
Flying Scotsman
LNER A3 pacific locomotive no. 4472 (BR 60103).
Flying Scotsman, The
Named train which runs between Edinburgh and London King's Cross.
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.

G

Gauge
Distance between the running rails (track gauge) or overall profile of a vehicle (loading gauge).
GLA
Greater London Authority
GRIP
Governance of (formerly 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).
GSM-R
Global System for Mobile communications - Railway. An international standard for voice and data communication between trains and control centres. It is a subsystem of ERTMS
GWML
Great Western Main Line
GWR
Great Western Railway

H

HAL, HAHL
Heathrow Airport [Holdings] Limited which replaced BAA.
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 were used to indicate the route but are no longer used on most types of train. Route numbers have been adopted for other services and are used on FGW Turbos.
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 - GWR name for services operated by HSTs.
HST
High Speed Train, also known as the InterCity 125 and used on FGW's long distance services.

I

ICC
Integrated Control Centre - see foll.
IECC
Integrated Electronic Control Centre (signalling centre).
IEP
Intercity Express Programme - programme to design and build a replacement for the HST
IET
Intercity Express Train - resulting from IEP and being built by Hitachi. Also known as SET
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.

L

LCD
Liquid Crystal Display - used for flat screen displays in PIS.
LED
Light Emitting Diode - used in modern signalling and PIS. Also increasingly used for lighting.
LENNON
Latest Earnings Networked Nationally Over Night - ticket sales database.
LEP
Local Enterprise Partnership (between local authorities, transport operators, etc.)
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. A platform loop allows a stopping train to call at a station leaving the through line clear for other traffic.
LOROL
London Overground Rail Operations Limited
LTPP
Long Term Planning Process
LTV
London and Thames Valley
LTW
London TravelWatch
LUL
London Underground Limited

M

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)
MDRS
Marlow and District Railway Society
MMPA
Marlow-Maidenhead Passengers' Association - user group for public transport users in the Maidenhead - Marlow and High Wycombe area including Twyford and Taplow.
MOIRA
Industry standard timetable based passenger demand forecasting model. It is a girl’s name, not an acronym.
MPD
Motive Power Depot
MRL
Mendip Rail Limited - company that operates stone trains on behalf of Foster Yeoman and Hanson (formerly ARC).
MTR
Mass Transit Railway - Hong Kong based rail operator which has a 30 per cent share in the new South Western Railway franchise.
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).

N

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.
NFC
Near Field Communication. This is the technology used for so-called "contactless" smartcards and smartphones including Oyster. The cards can hardly be contactless if you have to touch in and touch out!
NLRIP
North London Route Improvement Plan
Normal
Position of points when set straight ahead or along the main route cf reversed.
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 RDG.
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.

O

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 or OHLE
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 and Road (previously 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.

P

Passenger Focus
National rail consumer watchdog. (web site).
PCA
Passenger Communication Apparatus (emergency alarm on train)
PDF
Portable Document Format
PERTIS
PERmit to Travel Issuing System
PIDD
Passenger Information During Disruption
PIS
Passenger Information System, also known as CIS.
PiXC
Passengers in Excess of Capacity
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 mash-up of punctuality and reliability figures expressed as a percentage.
PRM
Persons with Reduced Mobility - Eurooean disability access regulations.
PRM-TSI
Persons with Reduced Mobility - Technical Standards for Interoperability.
PSR
Passenger Service Requirement - the minimum level of service required of a franchise.
PTA, PTE
Passenger Transport Authority / Executive
PTI
Passenger Train Interface
PW
Permanent Way - the railway track itself, and the track bed.

R

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.
RAB
Regulatory Asset Base - the asset value as determined by ORR for setting Network Rail’s income.
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.
Railfuture
Brand name for the RDS.
RAM
Route Asset Management (Network Rail team)
RBWM
Royal Borough of Windsor and Maidenhead
RCTS
Railway Correspondence and Travel Society
RDG
Rail Delivery Group - representing Network Rail and TOCs
RDS
Railway Development Society Ltd., pro-rail pressure group (web site).
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.
ROC
Regional Operating Centre
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.
RRV
Road-Rail Vehicle
RSPG
Railway Safety Principles and Guidance
RSSB
Rail Safety and Standards Board
RSSSG
Rolling Stock Strategy Steering Group
RT
Right Time (RT% = percentage of right time arrivals).
Running-In Board
Large station name board usually situated near the end of a platform so that it can easily be read by passengers as the train runs into the station.
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

S & C
Switches and Crossings - pointwork on the track. Also the Settle & Carlisle line.
S & T
Signals and Telecommunication
SDO
Selective Door Opening (to allow trains to stop at short platforms)
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.
SEFT
South-East Flexible Ticketing (a defunct government-sponsored scheme in Kent).
Set
A set of coaches or a multiple unit.
SET
Super Express Train - outcome of the IEP to be supplied by Agility Trains. There will be all-electric and bi-mode (with diesel engines for use off the wires) variants. Also known as IET.
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 levels that a TOC is committed to provide under a franchise.
Sleeper (1)
Transverse wooden, concrete or steel beam that supports the track and maintains the correct gauge.
Sleeper (2)
Sleeping car (with beds, couchettes etc for ovenight travel).
SLF
Subordinated Loan Facility - stake that must be put up by the parent group of a franchise bidder as insurance against the franchise holder walking away.
SLW
Single Line Working
SMIS
Safety Management Information System
SMS
Safety Management System
SoFA
Statement of Funds Available (to meet the HLOS)
SPAD
Signal Passed At Danger
SPATE
Speed Previously Announced Terminated Early i.e. a TSR that has been lifted earlier than planned.
SPIR
Significant Performance Incident Reviews
SRA
Strategic Rail Authority - now replaced by DfT Rail
SPT
Signal Post Telephone
SSI
Solid State Interlocking
SSR
SubSurface Railway (London Underground) - i.e. Metropolitan, District, Circle and Hammersmith & City lines.
SSRB
Special Speed Restriction Board (e.g. on approach to a level crossing)
Staff
An object that permits a driver to take his train onto a single track section that is operated as a siding. On the Marlow line there is a staff section between Bourne End and Marlow. Unlike tokens there is only one staff for the section so only one train can operate on it.
(Also means employees, but you knew that.)
STANOX
Station Number Code used within TOPS to indicate a particular piece of railway (siding, station, depot, etc.).
SWR
South Western Railway - TOC which took over from SWT on 20th August 2017. It is a joint venture between First Group and MTR.
SWT
South West Trains - TOC which operated services out of London Waterloo until 19th August 2017.

T

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).
TBM
Tunnel Boring Machine
TDM
Time Division Multiplex - type of data transmission.
TfL
Transport for London - transport authority for Greater London reporting to the Mayor of London.
Thameslink
Network of services linking north and south of the Thames via the Metropolitan Widened Lines between St. Pancras and Blackfriars.
TIPLOC
Timing Point Location - a unique six-character code allocated to each point used for timetabling purposes.
TMD
Traction Maintenance Depot
TMS
Traffic Management System
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 is a token section between Maidenhead and Bourne End. 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. cf Staff
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!
Train ID
Train Identifier - see Reporting Number
TRTS
Train Ready To Start - you may see a TRTS plunger or button on the platform at major stations. It is used by the dispatcher to indicate to the signalling system that the train is ready to depart. It is normally given shortly before departure time, when the train is crewed and provisionned as necessary. See also CD and RA (1).
TRUST
Train RUnning System TOPS - train movement data feed.
TSR
Temporary Speed Restriction
TT
Timetable
Turbo
Originally “Networker Turbo” (or “Thames Turbo” under Thames Trains) - the Class 165 and 166 diesel trains which work our local services. The Class 166 units are the ones with air conditioning. 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, under which authority is given for major infrastructure projects.

U

UAT
Universal Access Toilet
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.
URX
Under Road Crossing e.g. to take signalling cables under the road at level crossings.
UTX
Under Track Crossing (for cables, drainage etc.)
UWC
User Worked Crossing

W

VFR
Visiting Friends and Relatives

W

W
Whistle. You will usually see a “W” sign by the line when approaching a level crossing.
WHIRS
Wider Heathrow Integrated Rail Strategy
WLR
Windsor Link Railway - Scheme to link the two railways into Windsor via a single subsurface station.
WRATH
Western Rail Access To Heathrow
WRSB
Western Route Supervisory Board - which aims to bring NR and the operators closer together.
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.

X

X
(flattened X on trackside signboard) Level crossing. The board may show a speed limit for trains approaching the crossing.

Y

Y
Yellow. Railway signals have yellow aspects, not amber!
YY
Double Yellow (signal aspect)

Z


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Last updated 10th October, 2017