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
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
Words and abbreviations in yellow are defined elsewhere in the glossary.
A B C D
E F G H
I L M N
O P R S
T U V W
Click on the index letter to return to the top.
- Automatic Barrier Crossing, Locally controlled.
- Alternating Current - for traction usually supplied at 25kV, 50Hz by OLE.
- Association of Community Rail Partnerships
- Automatic Drop Down - a facility or activation thereof that drops the pantograph
of an electric train if it detects a fault in the overhead line such as the contact wire not being there. Unintended ADD
activations can occur if the contact wire rises too quickly after going under a bridge or other structure.
- 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).
- Now abandoned scheme by BAA to link Heathrow Airport via South-Western
metals to Reading and Waterloo.
- Automatic Number Plate Recognition
- 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.
- Automatic Power Changeover - which tells an IET when to switch between
electric and diesel traction.
- Company that operates car parks on behalf of GWR and Chiltern, amongst others.
- Assisted Passenger Reservation System
- Arr or a.
- Arrival Time
- Automatic Routesetting System - normally an integral part of IECC but can be
used with NX panels.
- All Signals Red - panic button on a signalling panel (aka “Stop All Trains”).
- Association of Transport Coordinating Officers.
- Automatic Train Operation
- Association of Train Operating Companies, now absorbed into RDG
- Advance Warning Board
- 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.
- 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.
- 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.
- Benefit to Cost Ratio
- describes a train that can use both electric and diesel traction.
- Axle configuration of a locomotive with two bogies each having two wheelsets
which are individually powered.
- British Railways Board (Residiary) Ltd.
- Bergische Stahl Industrie (now Faiveley Transport) - type of coupler used on our turbos.
- 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.
- 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.
- Axle configuration of a locomotive with two bogies each having three wheelsets
which are geared together.
- Computer Based Interlocking.
- Communications Based Train Control.
- Closed Circuit Television - used to monitor some level crossings, and for surveillance.
- Close Doors (signal to driver)
- The area on either side of the railway, outside the running rails.
- Controlled Emission Toilet (i.e. with retention tank).
- Short curve (actually an arc, not a chord) joining two intersecting railway lines.
- Community Infrastructure Levy - paid by developers (replaces section 106 payments).
- 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.
- 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.
- Cross London Rail Link - the organisation responsible for delivering Crossrail.
- Axle configuration of a locomotive with two bogies each having three wheelsets which are individually
- Control Period - a five year period used for railway planning. We are now in CP6 which runs from 1st April 2019 to
31st March 2024. CP7 runs from 2024 to 2029 and so on.
- Crossrail Limited
- 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.
- Chiltern Railways Passenger Board
- 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.
- Cab Secure Radio - now being replaced by GSM-R.
- Channel Tunnel Rail Link (now HS1)
- Disability Access Act, now replaced by the Equality Act.
- ATOC’s computer system for handling service disruption data across the network.
This will eventually interface with all the operators’ CIS.
- Deutsche Bahn - German Railways, parent company of Chiltern Railways, Arriva, DBS.
- Deutsche Bahn Cargo - new name for DBS freight operations in the UK.
- Deutsche Bahn-Schenker freight company that bought out
EWS, now DB Cargo.
- 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.
- 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.
- 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.
- Diesel-Electric Multiple Unit (with one or more diesel generators and electric traction motors).
- Dep or d.
- Departure Time
- Department for Transport - government department.
- DfT Rail
- Part of the DfT responsible for railways. It replaced the Strategic Rail
- 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.
- Docklands Light Railway
- Diesel Multiple Unit train.
Turbo used by GWR and Chiltern Railways on suburban services.
- Driver Only Operation. On the Marlow branch DOO is only permitted between Maidenhead and Bourne End.
- Directly Operated Railways - Government owned company which took over failed franchises East Coast until it was relet.
- Down or DN
- Direction of travel for trains heading away from London (or other major centre).
- Disabled Persons Transport Advisory Committee
- Diesel Trains Limited
- Driver’s Vigilance Device
- 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.
- Enhancement Cost Adjustment Mechanism - ORR review process to determine value for money.
- Empty Coaching Stock - i.e. an empty train running to or from a depôt or stabling point or between
- Electro-Diesel Locomotive - an electric locomotive with a diesel engine
for operation on non-electrified lines, e.g. Class 73.
- Elizabeth Line
- Brand name for Crossrail 1 (East-West) services.
- Electric Multiple Unit
- 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!
- Emergency Restriction of Speed
- 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.
- European Train Control System
- Brand name for services between London and Brussels or Paris via the Channel Tunnel
- English Welsh and Scottish Railway - freight operator, now DB Cargo (DBC).
- 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°.
- 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 Class A3 pacific locomotive no. 4472 (BR 60103).
- Flying Scotsman, The
- Named train which runs between Edinburgh and London King's Cross.
- Freight Operating Company
- Four foot
- The gap between the rails (actually 4' 8½")
- Facing Point Lock - to prevent the points moving under a passing train at a diverging junction.
- Distance between the running rails (track gauge) or overall profile of a vehicle (loading gauge).
- Greater London Authority
- 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).
- 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
- Govia Thameslink Railway (which operated the Southern, Thameslink and Great Northern franchise).
- Great Western Main Line
- Great Western Railway
- HAL, HAHL
- Heathrow Airport [Holdings] Limited which replaced BAA.
- 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.
- The minimum time between consecutive trains on a particular line.
- Heathrow Express - the fast service between Paddington and
- High Level Output Specification - sets the outputs that the government wished to purchase from the
railway industry during a Control Period (CP).
- High Speed One - high speed line between London St. Pancras and the Channel Tunnel, formerly
- High Speed Two - proposed high speed line connecting London with the Midlands and the North.
- High Speed Services - GWR name for services operated by HSTs.
- High Speed Train, also known as the InterCity 125 and used on FGW's long
- Integrated Control Centre - see foll.
- Integrated Electronic Control Centre (signalling centre).
- Intercity Express Programme - programme to design and build a replacement for the HST
- Intercity Express Train - resulting from IEP and being built by Hitachi. Also known as
- Initial Industry Plan - first step in deciding what can be provided in the HLOS for the next
- 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.
- Integrated Train Planning System - new NR timetable planning system.
- Integrated Transport Smartcard Organisation - body formed to draw up standard
specifications for interoperable smartcard based ticketing systems similar to (but not including) Oyster.
- Liquid Crystal Display - used for flat screen displays in PIS.
- Light Emitting Diode - used in modern signalling and PIS. Also increasingly used for lighting.
- Latest Earnings Networked Nationally Over Night - ticket sales database.
- 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.
- 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.
- 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.
- London Overground Rail Operations Limited
- Long Term Planning Process
- London and Thames Valley
- London TravelWatch
- London Underground Limited
- 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
- Multiple Aspect Signalling - i.e. colour light signalling with separate lenses on the signal head
(cf. searchlight signal).
- Marlow Branch Working Group, comprising MMPA, Bucks County Council, FGW,
NR, Wycombe District Council, Marlow Town Council and RBWM
- Manually Conterolled Barrier (level crossing)
- Marlow and District Railway Society
- Marlow-Maidenhead Passengers' Association - user group for public transport users in the Maidenhead - Marlow and High Wycombe area
including Twyford and Taplow.
- Industry standard timetable based passenger demand forecasting model. It is a girl’s name, not an acronym.
- Motive Power Depot
- Mendip Rail Limited - company that operates stone trains on behalf of Foster Yeoman and Hanson (formerly ARC).
- Mass Transit Railway - Hong Kong based rail operator which has a 30 per cent share in the new South Western Railway franchise
and will be operating services on Crossrail.
- 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
- Series of DMUs and EMUs of
Classes 165, 166, 365 and 465 introduced by Network SouthEast.
- 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!
- National Infrastructure Commission
- North London Route Improvement Plan
- Position of points when set straight ahead or along the main route cf reversed.
- Network Rail - the publicly owned company which owns the railway infrastructure
and signalling, and which operates principal stations such as London Paddington.
- National Rail Enquiries - enquiry and journey planning service run by RDG.
- National Station Improvement Scheme
- 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.
- Outline Business Case
- 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
signaller if vehicles or animals have to be taken across the line.
- 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)
- Operator of Last Resort (OLR1 runs the East Coast Main Line; OLR2 would be set up should GTR
be stripped of the STGN franchise.
- State of a signal at danger i.e. red (cf Off).
- 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).
- Operational Research Computerised Allocation of Tickets to Services - rail industry income allocation model.
- Office of Rail and Road (previously Office of Rail Regulation)
- OTDR, OTMR
- On Train Data (or Monitoring) Recorder - railway equivalent of the “black box”
- Brand name for surface rail services operated by LOROL on behalf of TfL.
- Smartcard payment system used by TfL and being extended to National Rail
services within the GLA area.
- The device mounted on top of an electric train which collects power from the overhead line.
- Passenger Focus
- National rail consumer watchdog. (web site).
- Passenger Communication Apparatus (emergency alarm on train)
- Portable Document Format
- PERmit to Travel Issuing System
- Passenger Information During Disruption
- Passenger Information System, also known as CIS.
- Passengers in Excess of Capacity
- Power Operated Gate Opening (for user worked level crossings).
- 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.
- Point Position Indicator (like a signal but only to indicate which route is set).
- Public Performance Measure - a mash-up of punctuality and reliability figures expressed as a percentage.
- Persons with Reduced Mobility - Eurooean disability access regulations.
- Persons with Reduced Mobility - Technical Standards for Interoperability.
- Passenger Service Requirement - the minimum level of service required of a franchise.
- PTA, PTE
- Passenger Transport Authority / Executive
- Passenger Train Interface
- 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.
- Regulatory Asset Base - the asset value as determined by ORR for setting Network Rail’s income.
- 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.
- A nationwide group which campaigns for better railways and the reopening of closed routes where viable.
Formally known as RDS.
- Route Asset Management (Network Rail team)
- Royal Borough of Windsor and Maidenhead
- Railway Correspondence and Travel Society
- Rail Delivery Group - representing Network Rail and TOCs
- Railway Development Society Ltd., pro-rail pressure group now known as Railfuture.
- 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.
- Points are said to be reversed when set away from the normal (usually straight ahead) route.
- Rail Head Treatment Train - to deal with icing of conductor rails and leaves on the line.
- The railway track. A train “has the road” when it has a route set ahead of it and the signal is
- Regional Operating Centre
- Rolling Stock
- General name for railway vehicles including locomotives, coaches and wagons.
- Rolling Stock Company - which leases trains to the TOCs.
- Rail Passengers' Council - now superseded by Passenger Focus.
- Route Relay Interlocking - type of interlocking using electrical relays.
- Road-Rail Vehicle
- Railway Safety Principles and Guidance
- Rail Safety and Standards Board
- Rolling Stock Strategy Steering Group
- 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.
- 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
- 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.
- South-East Flexible Ticketing (a defunct government-sponsored scheme in Kent).
- A set of coaches or a multiple unit.
- 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. Now usually known as IET.
- Strategic Freight Network
- Station Information and Surveillance Systems
- Six foot
- The gap between two adjacent tracks (cf. four foot).
- 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).
- 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.
- Single Line Working
- Safety Management Information System
- Safety Management System
- Statement of Funds Available (to meet the HLOS)
- Signal Passed At Danger
- Speed Previously Announced Terminated Early i.e. a TSR that has been
lifted earlier than planned.
- Significant Performance Incident Reviews
- Strategic Rail Authority - now replaced by DfT Rail
- Signal Post Telephone
- Solid State Interlocking
- SubSurface Railway (London Underground) - i.e. Metropolitan, District, Circle and Hammersmith & City lines.
- Special Speed Restriction Board (e.g. on approach to a level crossing)
- 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
(Also means employees, but you knew that.)
- Station Number Code used within TOPS to indicate a particular piece of railway (siding,
station, depot, etc.).
- South Western Railway - TOC which took over from SWT on 20th August 2017.
It is a joint venture between First Group and MTR.
- South West Trains - TOC which
operated services out of London Waterloo until 19th August 2017.
- A permanent way machine used to pack the ballast evenly
underneath the track.
- 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).
- Tunnel Boring Machine
- Train Care Depot
- Time Division Multiplex - type of data transmission.
- Transport for London - transport authority for Greater London
reporting to the Mayor of London.
- Network of services linking north and south of the Thames via the Metropolitan Widened Lines between St. Pancras and
- Timing Point Location - a unique six-character code allocated to each point used for timetabling purposes.
- Traction Maintenance Depot
- Traffic Management System
- Train Operating Company - company which holds a franchise to operate passenger rail services.
- 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.
- Total Operations Processing System - computer system used by Network Rail to keep track of all rolling
stock, motive power units, train consists, etc.
- Trains Per Hour
- 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.
- 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
- 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).
- Train RUnning System TOPS - train movement data feed.
- Ticketing Settlement Agreement
- Temporary Speed Restriction
- Originally “Networker Turbo” (or “Thames Turbo” under Thames Trains) - the
Class 165 and 166 diesel trains which work our branch line and some other 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 late 1980s.
- Thames Valley
- Thames Valley Signalling Centre (at Didcot)
- Transport and Works Act, under which authority is given for major infrastructure projects.
- Universal Access Toilet
- Union Internationale des Chemins de Fer (International Union of Railways).
- See Multiple Unit.
- Direction of travel of trains heading towards London (or other major centres). For cross-country routes it can be arbitrary.
- Under Road Crossing e.g. to take signalling cables under the road at level crossings.
- Under Track Crossing (for cables, drainage etc.)
- User Worked Crossing
- Visiting Friends and Relatives
- Whistle. You will usually see a “W” sign by the line when approaching a level crossing.
- Wider Heathrow Integrated Rail Strategy
- Windsor Link Railway - Scheme to link the two railways into Windsor via a single subsurface
- Western Rail Access To Heathrow
- Western Route Supervisory Board - which aims to bring NR and the operators closer together.
- 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.
- (flattened X on trackside signboard) Level crossing. The board may show a speed limit for trains approaching
- Yellow. Railway signals have yellow aspects, not amber!
- Double Yellow (signal aspect)