London Underground Glossary
London Underground has its own
language. Here is the start of a list of some the most commonly used terms and
expressions. More will be added from time to time.
A Stock - The original A Stock
was built for the District in 1903 as the test for the electrification of the line and
which were used on the Ealing and South Harrow line. The present A Stock is the
standard type used on the Metropolitan Line.
AFC - Automatic Fare Collection
Alps - The nickname given to
the sidings at the north east corner of Ealing Common depot where the tracks are at a
higher level than the rest of the depot.
Approach Controlled Signal - a
signal on London Underground which remains red, even if the route it protects is set and
clear, until the train has occupied a track circuit close to the signal. This form
of control is used to force drivers to reduce speed if required because of a curve or
Arrestor - A device located in
rear of buffer stops for absorbing a limited amount of the energy of a train which
overruns the usual stopping point at a terminus or dead end. The maximum speed for a
tube train reaching an arrestor cannot be more than about 20 km/h without the train
sustaining some damage.
ATO - Automatic Train
Operation, where the train speed is controlled by a combination of commands transmitted
from the track or trackside and the operator (formerly the driver) only has to start the
train and operate the doors. Used on the Victoria Line throughout and on the Central
Line except part of the Ealing branch. For more on Victoria Line ATO, click here.
ATP - Automatic Train
Protection, where the train is prevented, automatically, from passing a stop signal.
There are various ways of doing this mechanically and electronically. London
uses a trainstop system on most of its lines and electronic
systems on the Victoria and Central Lines.
Automatic Coupler - See Wedgelock Coupler.
Automatic Signal - A signal
which normally shows a green aspect. The signal is not provided with manual control
and responds to the condition of the track circuits controlling it. The signal will
go to danger when a train passes. It will automatically revert to a green aspect
when it is safe for trains to pass or a lunar white aspect when it is safe for automatic
trains to pass. See London Underground Signalling.
B Stock - The original wooden
stock introduced on the District for its main line electrification in 1905. It was
developed from the trial A Stock and originally comprised 420 cars formed into 7-car
trains. Some of it lasted into the 1940s.
Bakerloo - The line which was
originally the Baker Street and Waterloo Railway and which now operates between Elephant
& Castle and Harrow & Wealdstone. The route is coloured brown on the
Banjo - Shunt signal
(slang). See also Dolly and Signalling.
Block Joint - An insulated
joint fitted in a rail to divide two adjacent signalling sections by ensuring that the
track circuits of the sections are kept separate. See also Signalling.
Bostwick gates - Lattice type gates that are pulled
across an opening such as a station entrance or lift. Named after the company which
originally made them.
Branch, The - Slang
term for the Metropolitan Line north of Baker Street, dating from the time when the main
line was the section between Paddington and Farringdon and a single track branch was
opened to St Johns Wood. See also "Wood Line".
BRS Plate - British Reference
System. It's used to measure the distance from one station to the next. The distance
(usually every 100 metres) is marked by a BRS plate. For example, Walthamstow Central
Southbound on the Victoria Line is identified as V027 and, if you walk 200m along the
tunnel towards Blackhorse Road you'll see a BRS plate on a sleeper with
"V027 200 M" printed on it. It's mainly used to identify exactly
where a particular spot on track is.
A much better system is the chainage system,
which is referenced from one spot (on LUL it's Ongar), and everything is measured from
there. It's so much easier to calculate distances between 2 points using chainages
(called "Ongars" on LUL). Therefore, LUL uses BRS, while the whole rest of
the world uses chainages. Information in reply from "Jon" to a query
on uk.transport.london, 31 March 2002.
Buffer Stops - A device at the
end of a section of track to act as a marker and to allow a train to rest against them if
required. Normally also provided with some sort of arrestor device like sand, gravel
or mechanical retarder.
Busline - Term used by LU to
refer to a power cable running the length of a train or unit, which supplies all high
voltage systems. Buslines were forbidden on the tube lines and, in the days when
trains used 600 volt circuits for most control as well as power circuits, elaborate
precautions were taken to ensure that power connections between cars never carried the
full traction power current. The term originated from the word "omnibus"
(Latin for all), shortened to 'bus.
Button, Drop the - Phrase used
to indicate that the driver has released the vigilance device ("deadman")
causing an emergency brake application. Synonymous with "dropping the
deadman". The term "button" refers to older Underground trains which
were equipped with a button, in the centre of the master controller handle, which operated
the vigilance device. This type of handle is now only seen on some LU battery locos.
C Stock - The
original C Stock was a type of steel bodied stock built for the District in 1910, some
cars of which survived to the late 1950s. The later type is the C Stock, now the
standard type used on the Circle and Hammersmith Lines and on the Wimbledon - Edgware Road
service of the District.
CWR - Continuous welded rail -
Stretches of track where sections of rails are welded to make very long sections. It
eliminates fish-plated joints, where most rail defects occur.
Light - An orange light provided on cab ends of trains which, when
illuminated, signals to the driver of a following train to draw up to provide assistance,
usually when a "push out" is required by a defective train. The calling-on
light was first introduced on the 1967 Tube Stock because there was no guard on the train
to perform the calling-on function. The 1967 Tube Stock was the first train on the
Underground to be designed for one-person operation. Previously, trains carried a
crew of two, a driver and a guard.
Calling-On Signal - A type of
shunt signal used to permit trains to proceed into occupied tracks, usually for the
purpose of coupling to another train or unit. Not now regularly required and quite
rare. Samples survive at parsons Green (District) and Watford (Met.). Up until
the late 1960s all lines were equipped with them.
Cant - A standard railway term
describing the difference in level between the two rails of a track. The outer rail
of a curve is higher than the inner rail to counteract the centrifugal force of a train
travelling around the curve. The amount of difference in height of the two rails is
the cant. The maximum is 150mm.
Car - London Underground rail
vehicle. Replaces the usual British "carriage" or "coach".
Originated in the US because electric multiple-unit traction was imported from there into
Car countup and station limit markers - Indication
plates positioned along the track leading from a station platform, which carry a white
reflective number on a blue background. They provide the Train Operator with
information as to the trains position in relation to the platform following
operation of the passenger emergency alarm/brake. They count up the number of cars'
distance from the platform (up to eight).
Car Examiner - The now largely
defunct name for train technician. Also known colloquially as a "fitter".
Category A platform - A platform where the
Train Operator needs assistance from other staff to see the full length of the train when
OPO equipment has failed. If OPO equipment becomes defective the platform must be
staffed or trains non-stopped.
Category B platform - A platform where the
Train Operator does not need assistance from other staff to see the full length of the
train when OPO equipment has failed.
Centurion Manager - An operating manager
responsible for overseeing around 100-150 staff.
Cess - The space alongside the railway between the
ballast and a cable run or other boundary.
Chair Lock - A design of point
machine introduced on to London Underground in the early 1970s.
Check Rail - A length of rail
(on any railway, not just LU) which is fitted inside the running rails to assist in
preventing the train's wheel flange moving outside its normal gauge at points and
crossings and on sharp curves. It should not normally come into contact with the train's
Circle Line - Much maligned
route (yellow on the map) which forms a roughly circular (naturally)
route around the West End and City areas of London. It was originally built 1863 -
1888 to connect the main line stations around the edge of the then most built-up areas of
London. The service is particularly difficult to operate because of numerous flat
junctions which connect the line to various routes on the Metropolitan and District Lines,
with which it shares tracks.
Clamp Lock - A design of point machine introduced into
London Underground in the 1970s.
Clip & Scotch - A means of securing points which
have failed to operate or indicate that they have locked in the required position.
The clip is placed under the closed point blade and the stock rail to clamp the two
together. The scotch is pushed into the gap between the open point blade and the
other stock rail.
Collar - Any device provided for use as a reminder
that a lever, push-button, or switch must not be operated, usually in a signal control
Conductor Rail Ramps - Ramps (picture here) fitted at the ends of current
rails that allow the train's shoes to slide on and off smoothly.
Controlled area - An area where the
movement of trains is controlled by or affects the operation of semi-automatic signals.
CRID - Current Rail Indicator Device, used to show if
current is on. Not to be confused with Rail
Gap Indicator which shows where current is off. CRIDs have small orange lights
and are located at the end of some station platforms, just inside the tunnel.
Current rails - The two
additional rails provided on London Underground track to act as conductor rails for the
traction power supply. The trains collect current through cast iron
"shoes" provided on the bogies.
Customer - A person who
purchases from a shop. The same term is now applied universally by London
Underground to its passengers, even though the majority of them prefer to be called
passengers and even write letters to the papers to say so.
Continuous welded rail, a track type used by railways all over the world. It
eliminates plated joints, where most rail defects occur.
D Stock - The original D Stock
was a type of steel bodied stock built for the District in 1912, some cars of which
survived to the late 1950s. It was indistinguishable from the District's C Stock of
1910 (see above). The later type is the D78 stock, now the standard type used on the District.
A shortened version of "Deadman's Handle", the driver's vigilance device
consisting of a sprung power controller handle which, when released, causes the train
brakes to give an emergency application and to switch off traction power to the motors.
London Underground has always used controller handles for the vigilance device
rather than the pedals favoured by many other railways.
Detonator - A warning device, much
beloved of railways, secured to a running rail, which creates a loud bang when run over by
a train or mechanised vehicle. Used a a warning device to alert drivers that the
train must be stopped.
District Line - The sub-surface
line (green on the map) covering the southern half of the Circle and branches to the east
and west of London. Difficult to operate, like the Circle, because of the flat
junctions and variety of routes.
Dolly - Shunt signal
(slang). See also Banjo. See London Underground
Donkey Dick - (Slang) A ready
to start plunger provided in a siding so a driver can alert the signalman when he is ready
Dreadnought - A nickname given
to batches of Metropolitan Railway, locomotive-hauled coaches which first appeared in
1910. They were a considerable improvement on earlier coaches and were likened to
the new class of battleships then being built for the British Royal Navy. Photo here.
Dual Aspect - A signal showing
both proceed and stop aspects at the same time. This is normally due to the
trainstop failing to lower when the signal clears. The proceed aspect indicates that
the line ahead is clear but the stop aspect indicates that the trainstop has failed to
lower when the signal cleared. See also Trainstop.
Dump Valve - Brake valve used
on 1973 and D Stocks to dispose of brake cylinder air for remote brake isolation
purposes. The dump valves on 1973 Stock were originally linked to a wheelslide
protection system but it was taken off some years ago since it was found to aggravate the
occurrence of wheel flats.
E Stock - Type of steel bodied
stock built for the District in 1914, some cars of which survived to the late 1950s.
It was virtually identical to the C and D Stocks of 1910-12 except
that it had an elliptical roof in place of the usual District clerestory roof of the
ECEB - Electrical Control of
Emergency Braking -The system adopted on the 1973 Tube Stock and all subsequent trains,
where the on-train safety braking system is electrically monitored instead of the
compressed air brake pipe used on earlier stocks. A round-the-train circuit is used
to monitor the completeness of the train, brake functions and safety devices like the tripcock and deadman.
Electrical Control Room - A room provided
for the remote supervision of electrical substations.
Emergency release - A signalling control facility used
to release the electrical locking on signal and/or points levers or shafts.
Engineering hours - The period between the published
time or actual time, if later, traction current is switched off and the published time or
amended time, if earlier, traction current is switched on.
ERU - Emergency Response Unit. Used to be known as
"the Breakdown Gang".
F Stock - 100 cars of all-steel
stock built for the District in 1920 (Photo).
After the second world war they were transferred to the Metropolitan Line and were
replaced by the present A Stock in the early 1960s.
Fish & Parcels - Old slang
name for the District Line, since it runs over main line routes and was regularly alleged
to be subject to delays from other railways. In the days when it shared the two
tracks between Bow Road and Upminster with the London, Tilbury and Southend route,
District trains were regularly delayed by freight trains.
Four foot - The space between the two running rails of
a track. Originally from "four foot eight and a half inches", the gauge.
G Stock - Type of clerestory
roofed stock built for the District in 1923 and subsequently absorbed into the Q
Stock. All cars of this batch were originally motor cars.
current rails) - A section of track where the current rails are discontinued
because of points or a sub-station feed.
Gap Jumper - Portable
connecting leads often provided at locations where there are a number of current rail gaps
due to a complex junction. The leads are provided with a plug at one end to allow
connection with a receptacle box on a train, and with contact shoes at the other end to
allow them to be placed on the current rails. If a train becomes "gapped",
the gap jumper is used to connect a car on the train to nearby current rails. They
are awkward to use and need care to restart the train without dragging the leads or
running over them. Sometimes called gap leads.
Gapped - Getting
"gapped" occurs when a train stops with all its shoes off the current rails and
therefore without power to restart. Very embarrassing.
Gap, Mind the - Announcement
much beloved of London Underground management and offered at any opportunity where the
edge of the platform is more than a few millimetres distant from the sill plate at train
doorways. The expression had been used for many years at locations like Waterloo
(Bakerloo), where a large gap exists on a sharp curve. It was introduced at many
more locations in the early 1990s following the reduction of staff on platforms and a
subsequent rise in reported accidents to passengers. The expression is now the butt
of many bad jokes in London and is meaningless to passengers except as an irritant.
Guard - The person formerly
employed to operate the doors on an Underground train, look after passengers, ensure
right-time departure from stations, assist the driver in emergencies and provide rear
protection for the train if required in emergency. All trains are now
one-person-operated (OPO) and the guard's job is redundant.
H Stock - A batch of former B Stock
cars dating from 1905 and rebuilt in the mid 1920s for the District.
Handing - The identification system used by LU to
ensure that cars are coupled correctly and to identify the position of wheels and
equipment. More detail.
Headwall plunger - Equipment provided (usually only at
tunnel stations where there is a sub-station gap) to switch off traction current in an
Headwall tunnel telephone - A telephone in a sealed
box located on a platform headwall which is connected directly to the tunnel telephone
line system. It is used to switch off traction current in an emergency.
Headway Post or block marker board - Where a train in
automatic working will be stopped if the section ahead is occupied. The train will
automatically restart when the section ahead clears. It works similarly to an
automatic signal on Automatic Train Operating line(s) but does not display signal
aspect(s). See also Victoria Line ATO.
IMR - Interlocking Machine Room, where local
signalling control and interlocking equipment is located. The modern
equivalent is the SER or Signalling Equipment Room.
Jubilee Line - Tube line
originally opened in 1977 when it took over the Stanmore branch of the Bakerloo Line
combined with a new route from Baker Street to Charing Cross via Bond Street. An
extension to Stratford from Green Park was opened in November and the line to Charing
Cross was deprived of its passenger service. Grey on the map.
See also photos of the extension stations.
Jumper - Multi-core cable used
to connect electrical circuits between cars.
K Stock - Type of clerestory
roofed stock built for the District in 1927 and subsequently absorbed into the Q
Stock. All cars of this type were originally motor cars.
King Lever - A device in a signal cabin used to make
semi-automatic signals operate automatically. Now sometimes called "automatic
working switch", since levers are not so common.
Klondyke Sidings - The name
given to the sidings at Neasden Depot, which are laid between the main sheds and the main
Metropolitan Line. The sidings are connected to the fans at both ends of Neasden
Yard and are used for shunting movements as well as for stabling trains. The origin
of the name is unknown but it was suggested that it arose because they were first provided
at the time of the Klondyke gold rush of 1897-8. Also suggested by "Seek
Assistance" that the name arose because the trains used in the peak hours
were parked there during the middle of the day and at night and they were renowned among
train cleaners for being a treasure trove of coins which had fallen down behind the seat
Khyber Pass - Slang referring
to the small gateline section leading out of Kings Cross tube station ticket hall facing
towards the subsurface ticket hall.
L Stock - Type of clerestory
roofed stock built for the District in 1931 for the Upminster extension and subsequently
absorbed into the Q Stock fleet.
Leads - Portable cables used to
assist trains which have been "gapped" i.e stalled across
tracks where there are gaps in the current rails. The leads consist of a pair of
cables, one positive and one negative with a plug at one end and "shoes" at the
other end. The plug is fitted into a socket on the train while the shoes are placed
on the nearest available current rails. The power thus made available to the train
is used to move it far enough to allow its own shoes to make contact with the current
rails. The leads are then removed. Leads are usually stored in boxes at
locations around the system where long gaps in current rails are known to give problems to
Line Controller - A person located in a Line Control
Office to co-ordinate the day to day working of the railway.
Line diagram - A visual display in a signal box,
Regulating Room, Signalling Control Centre, Service Control Centre, or Line Control Office
showing the state of track circuits, signal aspects, the movement of trains, the position
of points at some locations and train descriptions.
LWR - Long Welded Rail, a track type like CWR. Information in reply from "JDikseun" to a query
on uk.transport.london, 31 March 2002.
Lookout - A person specially trained and used to warn
staff who might be exposed to danger from moving trains or vehicles.
M Stock - Type of clerestory
roofed stock, based on District rolling stock designs, built for the Hammersmith &
City Line in 1935 and subsequently absorbed into the Q Stock fleet.
Main Line - The pipe carrying
the compressed air supply for the train, which is connected between cars by hoses or
Main Reservoir - A compressed
air receiver mounted under each car (on most stocks) to serve as storage for compressed
air. Air is usually supplied at between 70 to 120 lb/in2.
Mate - The name used by a
trainman when referring to his colleague on a train in the days of two-person operation.
Mechanical Governor -
Device used on the Victoria Line 1967 Tube Stock to restrict the speed of the
train to 25 mph under certain conditions. It comprises a rotating device which uses
centrifugal force to open a contact in a circuit at a set speed (25 mph for the Victoria
Line ATO) to cause a control action. The same device is used in older lifts to
prevent overspeed. For an explanation of its use on the Victoria Line, see Victoria Line ATO.
Milking the tubes - A trick
used by dishonest booking clerks before computerisation when individual tickets were taken
from the middle of a sequentially numbered stack instead of from the bottom. This
prevented accurate accounting at the end of the day and covered for cash which was
illegally removed. The tickets were stored in vertical tubes and were designed to be
removed from the bottom of the tube as required for selling to passengers.
Accounting was done by noting the number of the first and last tickets sold of each value
and multiplying the difference by the face value.
Motor Alternator - A machine
provided on trains, built before the 1990s on London Underground, to supply low voltage
auxiliary systems like car lighting, battery charging and control circuits. It
consists of a 630 volt DC motor powered off the traction supply, which drives an
alternator. This alternator produces AC for lighting and for conversion to DC for
battery charging. the voltage levels vary from stock to stock. The modern
equivalent is called an auxiliary converter.
Motor Generator - A machine
which used to be provided on trains to supply low voltage auxiliary systems like car
lighting, battery charging and control circuits. It consists of a 630 volt DC motor
powered off the traction supply, which drives a DC generator. On London Underground,
the generator produced 50 volts DC for lighting, control circuits and battery
charging. It was superseded by the Motor Alternator. The modern equivalent is
called an auxiliary converter.
Motorman - The title which used
to be used by London Underground for a driver. It fell into disuse because of the
introduction of the title "Train Operator" which was used for trainmen employed
on trains equipped with ATO. Drivers were always promoted from guards who, in the
days of two-person operation, used to operate the doors and act as the second man in
emergencies and for train protection. Now, all drivers are officially called Train
Multi-aspect signalling - An area where a stop signal
can show a single yellow caution, double yellow caution or a green aspect provided the
section ahead is clear. Some signals are 3-aspect, showing only a single yellow in
addition to the green and some are 4-aspect, with the double yellow. The signal
will revert to danger when a train passes.
Mutual - The shortened version
of "a mutual changeover", the swapping of duties between station staff or
trainmen. By this process, two people could agree to swap duties and then inform the
supervisor by mutually signing a "changeover slip".
N Stock - Type of clerestory
roofed stock built for the District in 1935 and subsequently absorbed into the Q Stock.
Network Control Centre - (NCC)
the headquarters control room for the Underground system located at 55 Broadway,
London. Each line has its own control organisation but the Underground network is
monitored from the NCC. The role is one of co-ordination between lines and with
outside organisations like Railtrack, the police and fire services.
O Stock - Type of train, now
extinct, which was first introduced in 1937 for use on the Hammersmith and Circle
Lines. It had an unusual flared body profile, typical of the innovative design
solutions adopted by the Underground in the 1930s but sadly lacking these days. The
flare was intended to cover the gap between the train and the platform. During its
career, the stock worked over all the Underground's sub surface lines at one time or
another. It was unusual at the time in having the guard's controls in the driver's
cab, as it was the intention to convert them to one-person operation. This was never
done in the lifetime of the stock. The O Stock was soon absorbed into the next batch
of cars known as the P Stock and they operated together. The O Stock had an unusual
type of traction control known as the Metadyne, which was intended to allow regenerative
braking. The system gave much trouble in service and was converted to PCM control
over a 5-year period in the late 1950s and early 1960s. Photo
Off - of a signal, meaning that
the signal is showing a clear or proceed aspect.
On - of a signal, meaning that
the signal is showing a stop or caution aspect.
On the cushions - When a train
operator's 'next pickup' requires that he rides back on a train to his home depot, he is
said to be going "on the cushions" or "on the covers".
Similarly, if a train driver has only one train left to pick up in his duty, that train is
cancelled and he is nonetheless told to go to his next pickup, this is code for 'go home'
which his manager cannot directly say since he is being paid to the end of his duty
even though there is nothing else for him to do.
On-track plant - Self-propelled rail mounted
mechanical equipment used during the construction and maintenance of railway
OPO - One Person Operation; the standard
train operating regime used on London Underground. Conversion from two-person crews
began in 1984 and was finally completed in 2000.
Out of Gauge Rails - Rails which do not
retain the required distance between them. Rails on LU should be 1432mm apart (or
1435mm on flat curves, 1438mm on tight curves). If they're not, the rails are out of
gauge. Information in reply from "JDikseun" to a query on
uk.transport.london, 31 March 2002.
Overhead Leads - The standard LU shore
supply system for trains in depots where there are no traction current rails. A
simple, two-rail electrified track is suspended from the shed roof and a trolley slides
along the rails so it can be positioned anywhere along the road(s) it supplies. A
pair of insulated leads (positive and negative) hang from the trolley to floor level and
are equipped with a plug. The plug is inserted into a socket provided on certain
cars of the train to provide power. The socket is called a receptacle. On
stocks built in the 1990s, this socket is equipped with an isolating switch to prevent
collector shoes from being made live when the overhead lead is inserted. More details and photos here.
P Stock - Type of train, now
extinct, which was first introduced in 1938 for use on the Metropolitan and District
Lines. It was very similar to the O Stock except that it had the guards controls in
the passenger saloon, as on other Underground stocks. During its career, it worked
over all the Underground's sub surface lines at one time or another. It was quickly
absorbed with the O Stock and was soon formed into mixed trains of O/P Stock. It
had an unusual type of traction control known as the Metadyne, which was intended to allow
regenerative braking. The system gave much trouble in service and was converted to
PCM control over a 5-year period in the late 1950s and early 1960s.
Passenger Emergency Alarm (PEA) - A system provided on
trains for passengers to communicate to the Train Operator that an emergency situation is
Passenger Emergency Alarm Brake - A system on a train
that, when operated by activation of a passenger emergency handle, will alert the Train
Operator to a problem and will automatically apply the brakes. It can be over-ridden
by operating a brake release floor switch. This is to allow a train to
continue to the next station where assistance can be provided.
PCM - Pneumatic Camshaft
Mechanism - The name used by LU for the traction equipment used on its trains which are
equipped with pneumatically operated power resistance controllers, i.e. any stock built
before 1992. The name is derived from the US system known as PCC control, in turn
derived from the President's Conference Committee of the American Institute of Electrical
Phantom signal - A semi-automatic stop
signal in an ATP area (Central Line). It does not display a colour light aspect but a
target speed is displayed in the Train Operators cab. Its location is
identified by a sign showing its signal code.
Pictures - The name of the
siding at the eastern end of Northfields Depot, which was used for shunting and which was
close to the local Cinema.
Pipe - see Rounder.
Plunger (1) - A button mounted
outside the train which the driver presses to indicate to the train regulator (or
programme machine, or signal computer etc.) that he
is ready to start from a siding or platform. Information in reply from
"JDikseun" to a query on uk.transport.london, 31 March 2002.
Plunger (2) - A small piston in
the pump of a track or flange lubricator. The train wheels depress the plunger as
they pass, pumping grease onto the spreader bar. The flanges of the wheels pick up
the grease from the spreader bar (sometimes, when you're lucky) and then (sometimes, when
you're really lucky) deposits the grease onto the gauge corner of the rails. The
grease reduces wear of the rails (so extending the life of the rails to reduce costs) and
cuts down the noise called flanging. You can always tell when the greaser
(lubricator) isn't working - you hear the high-pitched squeal. Information in
reply from "JDikseun" to a query on uk.transport.london, 31 March 2002.
PNR - Physical Needs Relief -
The use of spare staff to allow a person to leave his post or duty to use the
lavatory. The facility is much abused by trainmen to obtain a break from the
tedium of train operation in tunnels, even if they don't need it for natural causes.
Sometimes referred to as a "physical" or a "sh*t relief".
The spare person takes over part of the duty of the person requiring the "PNR",
including part of the trip within a train operator's duty.
Porter's button - A button provided at
the end of each car, normally a black rubber disc but can be white or grey, used for
closing the train doors on that car only.
Position light shunt signal - A shunt signal that will
show two red lights horizontally when at danger. It shows one white light when
clear. A newer type of shunt signal seen on LU since the resignalling of Neasden
Depot in the 1980s.
Possession - A section of track which has been
relinquished by the operating railway to the engineer. Control is in the charge of a
Possession Master. Unauthorised train movements into the section are prevented by
special protection arrangements.
Possession Master - A person specially trained and
certificated to take control of and give up a possession, in order to carry out
engineering and similar work.
Protection - Procedures to make sure staff on the
track are not endangered by a moving train or mechanised vehicle.
Protection key switch - A signal control device used
to maintain semi-automatic signals at danger to provide protection for staff entering
tunnels during traffic hours.
Protection Master - A person certificated by LUL to
provide protection for himself and others on or about the track.
Punters - Slang term for passengers.
Push Out - The rescue of a failed train by the
following train, which is used to provide power by pushing the defective train to the
depot. The process invariably causes a long delay because the coupling is slow
(largely due to unfamiliarity of the crew with the coupling system, since they don't get
to use it very often) and the two trains must be detrained one after another at the next
station. Speed is severely restricted and the double length train causes track
circuits to respond in unusual ways - normally locking signals at danger, causing further
delays. Not to be recommended.
Q Stock - Type of old rolling
stock used on the District until the early 1970s. It was formed from a mixture of older
stock and some new vehicles introduced in 1938. The mixture of the old and new cars
gave the stock a disorganised appearance. Photo here.
'R' board - A sign displayed at a station when there
is defective trackside radio equipment ahead. It is red or white and has a black
"R" with a white cross.
R Stock - District Line rolling stock
introduced in batches from 1947 to 1959. The 1949 batch (known as R49 Stock) was the
first London Underground stock to be constructed with aluminium bodies and some cars were
delivered with unpainted bodies. This experiment was so successful that unpainted
bodies were universally adopted by LU until the 1992 Tube Stock. Photo here.
Rail anchor - A device which when applied
to the foot of the running rail and in contact with the chair resists the longitudinal
movement of the rail. The name was originally used (and is still) to mean a train
anchor. See also train anchor
Indicator (RGI) - Explanation and
Railing - The act of moving a
train in a shed without current rails so that the leading car is standing on current rails
outside the shed. Photo here.
Ramp, current rail - Sloping
end of a current rail designed to allow the collector shoes to ride onto and off the rails
without damage. In addition, wooden ramps are provided at switches and crossings to
ensure that low shoes do not strike rails. Photo
Ramping - The noise made by the
3-phase traction control on the 1996 Tube Stock during acceleration and braking.
This is due to the GTO thyristors used on this type of control. It does not occur on
the 1995 Tube Stock because it has IGBT control.
Refuge - A temporary place of safety within a limited
Regulating Room - London Underground speak
for signalling control centre.
Regulator - London Underground speak for
control room operator.
Relief - The act of changing a
crew or staff at station or signal control position. Also used as a noun as in
"My relief is here".
Repeating signal - A signal that indicates the aspect of the
next stop signal. It will show a yellow caution aspect if the next stop signal is
showing a red aspect or green aspect if the next stop signal is also showing a green
aspect. This is not a stop signal as it is not provided with an associated
Reverser (1) - The traction
control system device provided on a train to allow it to be driven backwards.
Usually only used in depots or under very rare emergency conditions
Reverser (2) - The name given
to a train trip where the train turns back short of the end of the line as in "That
train is a Colindale reverser".
- Used to operate the master controller in the driver's cab where, traditionally, it
was provided for Forward, Off and Reverse positions. Also known as the
"Selector Key", where it performed other tasks in addition to obtaining forward
and reverse movement, on C Stock and 1967/72 Mk I & II Stocks.
Reversing Siding - A siding,
usually located between the two running lines, where trains can be turned back or
reversed. There are a number of such locations around the LU system, those in
tunnels rarely used because of the slow speed enforced on the run in to a dead end now
that LU can't trust their drivers not to end up in the tunnel wall.
RKL 220 key - A Yale type key which was first introduced on the 1973 Tube
Stock. It is used to open and close the Master Control Switch and which, when
removed, will secure the train. Tubeprune remembers that the first batch of these
keys caused a lot of trouble because they used to break off in the lock.
Rolling Stock - has a whole
page to itself here.
- (Slang) a return trip for a train driver's single or return trip. Also known as
"A Pipe" as in "up the pipe" where a crew has to do a trip through a
Running line - Any part of the railway
line not in a depot or siding.
SCAT - Speed Control After Tripping -
A device fitted to non-ATO trains on London Underground to ensure that a slow
speed is enforced on trains which have passed a signal at danger. The speed is
limited to 10-15 mi/h for three minutes.
Scotch Block - A device used to secure a
train stabled on a gradient. It consists of a wooden block shaped to fit on the rail
under the leading wheels of the train. A handle is provided at the side to make
fitting and removing the device easier.
Section Ahead/Section in Rear plungers -
Equipment provided at certain tunnel stations where a substation gap is just ahead or to
the rear of the station platform. They can be used to switch off traction current.
Sectionalisation Gap - Special
current rail gap at certain substations which is longer than the span of the current
collector shoes of a car so that the car does not become a "bridge" between one
traction current section and another. They are normally 15 metres long. More detail here.
Selector Key - The name used
for the reverser key as used on stocks built from 1967, where it is turned upside down and
inserted into a key barrel to switch in the driving control selector in the cab. The
selector key is part of the set of two (with the control key) that drivers of older stocks
always have to carry with them. C Stock, A Stock, 1967 and 1972 Tube Stocks need both
selector (still called the reverser key in the case of the A Stock) and control keys. The
1973 and D Stocks use the RKL220 and a control key. The 1992s, 1995s and 1996s only
need the RKL 220 on its own. When they first appeared the RKL 220 keys used to break
off in the lock and they had to be replaced by a stronger version. They are also
used for resetting passenger alarms. See also Reverser Key.
Semi-automatic signal - A stop signal controlled from
a signal box, control room or interlocking. The signal will show a green aspect only
when operated by the signaller, programme machine or computer, provided the section ahead
is clear and any points have been correctly set. The signal will automatically
revert to danger when a train passes.
Senior Signal Operator - A qualified person on duty in
a regulating room. Usually known as a "regulator".
Set Number - The unique number
allocated to each train in the working timetable (WTT) which identifies the trip worked by
that train. At the end of the trip the train will carry the same number through to
the next trip. The train retains the number throughout its working duty. The
number is displayed at the front and rear of the train.
Shed Receptacle -
Most stabling and maintenance sheds on London Underground are not provided with current
rails, so they are equipped with a shore supply system known as "overhead
leads", consisting of plugs suspended from trolleys running on roof mounted
rails. The leads plug into "shed receptacles" (sometimes referred to as
"receptacle boxes") provided on motor cars. More information here
Shoe - Cast iron collector
attached to insulated beams mounted on the bogies of electric trains. The
"shoe" slides on top of the rail as the train progresses so that power can be
collected almost constantly.
Short Circuiting Device (SCD) - A portable device that
is placed across the traction current rails to short circuit traction current. It
will switch off traction current or reduce traction current voltage in open sections and
it will prevent traction current from being switched back on. It is not used to
switch off traction current except in an extreme emergency, when no other means is
available. At some locations a short circuiting device will only reduce the
traction voltage, not switch it off.
- A special type of stop signal which, when cleared, permits movement at caution speed
into a siding or over a crossover. Normally, trains carrying passengers are not
permitted to proceed under the control of shunt signals because full interlocking may not
Siding(s) - A place where trains can normally be
stabled, other than in a depot.
Signal box - A room other than the Signalling Control
Centre, Stratford Market Depot Control Tower, Service Control Centre, Line Control Office,
or regulating room where operating staff control the fixed signalling.
Signal Post Telephone (SPT) - A telephone
located at a signal and connected directly to the signal or control centre, a signal box
or a station.
Signaller - The new term for a
signalman - another crude attempt at political correctness. "Signaller" is
actually a rank in the Royal Navy.
Signalling or regulating room - A place where
operating staff control and supervise fixed signals in areas equipped with programme
machines or computer equipment.
Six foot - The space between
one track and another where the lines are the normal distance apart.
Solebar - Principal side structural member of car
body shell or bogie. On a car body, the solebar usually forms the side of the
Speed inductor - A short
section of dummy positive current rail that measures the speed of a train by detecting the
motion of the train's collector shoes over the rail. It normally works in conjunction with
a speed controlled signal.
Standard Stock - A name given
to the large group of tube rolling stock built in batches between 1922 and 1934 for the
Northern, Piccadilly and Bakerloo Lines. The stock was finally withdrawn from
passenger service on London Underground in 1966. The name was also used for early District
stock when the stock built in 1905 for the original electrification was known as
"Standard Wooden Stock" from 1910 when steel-bodied stock began to be used.
Starting Signal - The signal
located at the departure end of the platform which, when cleared, permits the train to
leave the station.
Station limits - The platform area and a
train's length either side of the platform.
Stick - signal (slang).
If you "hit a stick", it means you have been tripped at a red signal because you
tried to drive your train past it and your train has stopped. Nowadays it is called
a "SPAD" (Signal Passed At Danger) in the UK.
Stops - Shortened name for
"buffer stops". Only referred to as "buffers" by anoraks.
Substation - A building housing equipment
for controlling the supply of traction current to sections of the railway. More detail here.
Substation Gap (also known as
"current rail gap") - location where there is a gap in the current rails between
two sections fed by the substation. Current is supplied to the current rails from
substations, in sections usually about 2 - 5km long. Some information in reply
from "JDikseun" to a query on uk.transport.london, 31 March 2002.
Suicide Pit - Explanation and Photo.
'T' board. Shows that the headwall telephone and/or
tunnel telephone wires in a traction current section might be out of order. Should
not be confused with the T sign used on the Underground to show the
"termination" of a speed restriction.
Tango Coat - Orange HiVi coat
worn by Train Technicians, operating officials and Instructor Operators.
Target - A portable pre-worded warning board usually
used to denote some person working on or repair activity taking place on a train.
Also used to warn of scotch blocks or rail anchors applied to trains.
TCB - Ticket Collector's Box.
Ten foot - The space between
one line and another where a wide space is provided between one pair of lines where there
are three lines or more.
Tip out - Detrain passengers
Train Position Detector -
Normally a delta track circuit, which operates when the train passes over the its
location. Used normally to trigger speed control sequences, or to release locking on
backlocked signals. A recent type of train position detector to appear is the axle
counter type, where the passing wheel flanges register through a magnetic field generated
by the detector. Some information in a reply from "JDikseun" to a query on
uk.transport.london, 31 March 2002.
Train Operator - The person who
drives and controls the operation of the train, including those working lines where ATO
(Automatic Train Operation) is provided. Nowadays, London Underground has a
requirement for about 3000 "drivers", of which, currently, around 100 are
females. There is often a shortage of train crew, amongst other staff and LU have
occasional recruitment drives. The annual salary for a train operator is currently
about £30,000. Training (described here) lasts for
Track/shed switch - A three position switch on 1995/6
Tube Stock trains with three positions as follows:
- SHED, allows 630V train equipment to be powered from the
overhead trolley leads
- OFF, isolates all 630V train equipment on the train
- TRACK, allows 630V train equipment to be powered via the
Traction current isolating switches -
Housed in yellow boxes and consisting of two switches, one positive and one negative, used
to isolate a siding or terminal track from the traction current supply. These are normally
- A weekly internal publication listing new engineering works, signalling alterations,
speed restrictions and other operational data for railway operating staff.
Train anchor (usually referred to as a
rail anchor) - A device used to anchor a train or vehicle to the running rail to prevent
it rolling away. Normally used only to stable a train on a gradient.
Train stopping mark - An enamel plate
consisting of a black background with a large white diamond - often mounted on a raised
wooden board, in the four-foot to indicate to driver the point at which the cab should be
when the train has stopped in the correct location in a platform. Sometimes a number
replaces the diamond to indicate where trains made up of differing numbers of cars should
stop, e.g. 6 or 8.
- A mechanical device fitted to all stop signals on London Underground and on Railtrack
routes over which LU trains operate. The device consists of a moveable arm which is
raised when the signal is showing a stop aspect and lowered when a proceed aspect is
shown. If a train passes the signal when the arm is raised, a tripcock
on the train is activated to cause an emergency application of the brakes. This is,
in effect, a mechanical form of ATP.
The design of the trainstop is fail-safe
inasmuch as it it lowered, if the signal shows a proceed aspect, by air pressure against
spring pressure. A failure of air pressure causes the trainstop to rise and it is
connected to the signal so that if it does rise under such a condition, the signal will
show a red aspect as well as the green. This is known as a dual aspect.
Tripcock - A
mechanical device fitted to LU trains on non-ATP fitted lines, which is activated if a
train passes a signal showing a danger aspect. If activated, it causes an emergency
brake application on the train.
Tripcock Tester - A gauge
mounted at the trackside to allow the tripcocks of passing trains
to be gauged for correct position and height. They are spaced at intervals along the
line. On the Piccadilly Line, for example, they are located at Wood Green,
Piccadilly Circus and Acton Town. As the train enters the station, a blue lamp is
illuminated near the starting signal. If the tripcock on the train successfully
passes through the tripcock tester, the lamp will be extinguished. If the lamp
remains lit, the train will be taken out of service.
Tripped - If a train passes a
red signal, the emergency brake is automatically applied. This is known as
"getting tripped". See also Tripcock and Trainstop.
Trip Valve - An
electro-pneumatic valve provided on the 1967 Tube Stock which provides an emergency brake
application in the event of a fault or unauthorised action detected by the train's ATP
system. It acts in the same way as the tripcock on a
manually driven train. If a 1967 Tube Stock train has to be driven over non ATO
lines, tripcocks have to be fitted to the ends of the train so that it complies with the
signalling system. The trip valve is isolated under these conditions since there are
no ATP codes to operate it. A Trip Valve/Tripcock Changeover Cock is provided on the
1967 Tube Stock to allow the changeover to take place when the train is transferred from
the Victoria Line to the Piccadilly Line at Finsbury Park, where crossovers between the
two lines are provided.
Tunnel Headwall - The front end-wall of a
platform in an underground station. Photo here.
Tunnel telephone (fixed) - A dedicated telephone,
provided instead of tunnel telephone wires, fitted on the left hand side of the track at
61 metre intervals alternately placed either at cab level or at about 1.2 metres from
track level and connected directly to the Line Controller. It is used to switch off
traction current in an emergency.
Tunnel telephone (train borne) - An independent
communication device for use between a stationary train or vehicle and a Line Controller
when it is necessary for a Train Operator to switch off the traction current supply in a
tunnel section. Using the tunnel telephone for this purpose automatically connects the
Train Operator to the Line Controller. It can be used in an emergency when the train
radio is inoperative. Using the tunnel telephone for this purpose automatically
switches off the traction current supply in the tunnel section.
Tunnel telephone system - A safety system used to
switch off traction current in an emergency and to communicate with the Line Controller.
Tunnel telephone wires - Two parallel copper/bronze
wires normally fixed along the left hand tunnel wall. When pinched together,
traction current is switched off on that section.
Ve - A standard railway term
for the equilibrium speed around a curve, where the cant exactly offsets the centrifugal
force. Information in reply from "JDikseun" to a query on
uk.transport.london, 31 March 2002.
Vickers - The nickname for the Metropolitan
Railway electric rolling stock built between 1927 and 1931 which, when formed into
multiple unit trains with various batches of converted steam hauled coaches, became known
as the T Stock in London Transport days. Metropolitan Vickers was the name of the
company which suppleid the elctrical equipment for most of these trains.
Vmax - The maximum speed that a
train can safely travel around a curve (which will be higher than the Ve). Information
in reply from "JDikseun" to a query on uk.transport.london, 31 March 2002.
Coupler - The standard automatic coupler used on London Underground rolling
stock (drawing and description here).
It was originally designed in the early 1930s, using an idea from the US based on the old
Tomlinson Coupler. The purpose of the coupler is to allow two units to be pushed
together and couple automatically complete with all mechanical, electrical and pneumatic
connections. The original design allowed the electrical and mechanical connections
to be controlled from a push button in the cab. Uncoupling was also started by a
push button and the two units would disconnect and push apart. All the driver had to
do was release the brakes on the train before he operated the uncouple button.
The trouble with this coupler was that, in its
original form, it was too complicated. It would only uncouple if the couplers on the
two vehicles released at the same moment and this only happened if both the air operated
disconnecting cylinders worked at the same time. Often, this did not happen.
Some bizarre rituals had to be gone through to get units to uncouple, including attempts
to manually lift both uncouple valves (one on each unit) with two staff calling out
"one, two, three, lift" in order to make sure they did it together. If
this failed, they would drain all the air off the train and try to force the coupler
pistons back against the springs by using long crowbars. Finally, if that failed,
the fitters would reverse the air pipe connections to try to force air into the uncouple
cylinders permanently which the train was driven apart. More recent versions have
had some improvements, including manual operation from each unit. Standard railway
couplers would be difficult to use on tube cars because of the clearances, which is why
the Wedgelock design has survived for so long.
Westinghouse Brake - The
standard air brake system used by London Underground (and many other railways around the
world) for about 100 years until the arrival of the 1973 Tube Stock. It was invented
in the US by George Westinghouse and was first used in the UK on the District Railway in
1875. The system uses compressed air as the control and operating medium. A
brake pipe runs the length of the train and is used to control and supply air to the brake
equipment on each car.
Wood Line, The - Slang name for
the Metropolitan Line north of Baker Street, dating from the time when the main line was
the section between Paddington and Farringdon and a single track branch was opened to St
Johns Wood and was called the St Johns Wood Railway. See also The