Signs, Whistle Codes, Flag and
Hand Signals

Signs & Symbols

Q. What do the various symbols found by railway tracks mean?

Many of the track-side signs and symbols appear on the left hand side of the track (the assistant driver's side), usually placed a little high and painted on a yellow board.

Speed Limit Number on triangular yellow board : speed limit in km/h. 'KMPH' or 'KM/H' may optionally appear below the number. Black text.

Sometimes the board has additional text, for instance 'RAJDHANI ONLY' may appear at the bottom, indicating that the speed is restricted for the Rajdhani service on this stretch.

Speed indication board

Speed Limit - Rajdhani/Shatabdi Number on blue board: indicates a special speed limit (in km/h) for Rajdhani and Shatabdi trains. Text is in white. (But see above -- sometimes the normal speed limit board is used with additional annotations for these trains.)

Rajdhani / Shatabdi speed indicator board

Termination Indicator T (painted on a yellow circular board) : Termination of speed limit

Termination Indicator board

Termination Indicators T/P, T/G, or T/BOXN (painted on a yellow circular board) : Termination of speed zone for, respectively, passenger trains, goods trains, and goods trains with BOXN wagon rakes. In urban areas similar signs such as T/EMU, T/EMU-9, etc., may be seen (termination of speed limit for EMU rakes, EMU rakes with 9 coaches, respectively). Other termination indicators seen include T/PG (for both passenger and goods trains, seen on ECoR), T/P24 (for 24-coach or longer passenger trains), and T/L (for local, i.e., suburban trains, usually EMU or DMU trains). The Hyderabad area MMTS system uses a T/M sign for its trains. T/R is sometimes seen for railbuses. Occasionally, the sign T by itself is shown to indicate a termination of speed limit for all trains. A T/Raj sign was in use for Rajdhani trains when they were first introduced but is no longer used now. WR used T/Raj indicators for the 8-coach Bombay - New Delhi Rajdhani, and its EMUs used the same sign as a termination indicator.

Termination Indicators

Caution Indicator Arrow-shaped boards pointing to the left or right. These indicate special restrictions on the track (temporary or permanent engineering restrictions) and caution orders in effect; the direction of the arrow indicates which track the restriction applies to. These boards are usually reflective yellow with black markings. The post on which it is mounted has alternating black and white bands. At night, sometimes two yellow lamps illuminate this indicator, although such lighting is not common and perhaps used more for caution indicators that are installed permanently. More often, the reflective paint on the indicator suffices for visibility at night. The caution indicator is usually placed 700m before a Speed Indicator board (see below) and 800m before the actual point of permanent way work or other cause of restriction. Drivers have to slow down to the speed indicated on the speed restriction board by the time they reach it.

Caution Indicator board

Other indicators include 'CP', or 'CG' on small white circular boards. These are caution indicators for passenger and goods trains, respectively. A 'C/T' indicator has been spotted in a few cases just before the entrance to a tunnel.

Warning Indicators (Vulnerable Point Indicators) A 'P' in a triangular or square board (black on yellow) advises the driver to be vigilant for track defects or obstructions on the track because of landslides, floods, etc. An 'E' in a similar board marks the end of the track section for which such advice applies (usually this is the rear of the matching 'P' board for trains approaching from the other side). A 'V' sign is often seen before entrances to tunnels or at other points in hilly terrain, etc., where there is a danger of landslides or rockfalls. It is also sometimes seen at the beginning of a bridge.

Refuge Indicators An 'R' in black on a small yellow circular board signifies a refuge or relief point on a section of track going through a bridge, tunnel, or cutting where clearances are tight. Workmen or their trolleys and other equipment on the tracks when a train is approaching can take refuge at these points.

Stop Indicator A rectangular board with red and white bands. It is mounted on a post with alternating red and white bands. At night the sign is illuminated by two red lamps. This is used for temporary or permanent engineering restrictions which call for trains to come to a dead stop before proceeding.

stop indication board

Some stop indicators are used to mark the spot beyond which a locomotive must not proceed when a signal ahead is at danger. These include vertical poles with 'STOP' spelled out in black on yellow, or rectangular yellow boards with 'STOP' on them in black. The poles usually have horizontal yellow and black stripes. A single white lamp may appear within the sign. These signs may appear on the right or on both sides of the track. At stations these stop signs are used to position the train correctly along the platform. (Sometimes, an indication board (see below) is used instead, with a message (black on yellow) such as 'Stop here when main signal is at danger', or 'Engine stop here'.)

Level Crossing indicator A black 'L' on a square yellow board indicates approach to a level crossing.

level crossing board

Whistle Indicators 'W', or 'W/L' on a square yellow board. The 'W' is a general whistle indicator while the 'W/L' stands for Whistle for Level Crossing. The latter is also seen in Hindi with the characters 'see/pha' == 'seetee bajao - phatak'). Usually provided on approach to unmanned level crossings (and for manned level crossings without a clear view) about 250m away from the level crossing. Similarly, a 'W/B' sign is seen (less often) on approach to a bridge.

whisle boards

Caution Order for Tunnel 'C/T' in black on a round yellow board. Caution Order in effect inside a tunnel; the sign is placed just outside the entrance to the tunnel. It is not known if this sign is used on any railway other than on Konkan Railway.

Caution Order for Tunnel Caution Order for Tunnel. Picture by Ashish Kuvelkar, May 2010.

Grade Indicator Ground level signs on a concrete slab base, with a number and an upward or downward pointing arrow, indicating a grade. A number '500', for instance, indicates a grade of 1 in 500. Black on white.

grade indicators

The arrow is often simply a 'v'-shaped mark instead of a full arrow symbol. A similar sign without an arrow and an 'L' instead of a number indicates the end of the grade.

There are some newer gradient or incline warning signs that are not on the ground as the ones described above but fitted to poles or catenary masts. They are usually yellow with blue or black arrows (although some blue signs with white arrows have been seen) with reflective paint, indicating upward or downward gradients; a double-headed (bidirectional) arrow is used to indicate a level section. The difference between these and the ones described above is that these are placed about 500m-700m in advance of the gradient they refer to, whereas the conventional grade indicators described above are placed at the point where the gradient or level section begins. The gradient indicators on catenary masts are also often accompanied by signs advising drivers to power up for the gradient.

Sighting Boards The most common kind of signal sighting board is a rectangular reflective board with a circle and two horizontal lines, yellow on black. This warns the driver of a signal ahead. The next signal should be visible from this point onwards, although in practice experienced drivers spot the signals well before the sighting boards are crossed. In lower quadrant territory, there are often two sighting boards used for signals. One, as described, is the goods signal sighting board and is placed 1400m before the signal. The other is the passenger signal sighting board intended for use by drivers of passenger trains and is usually placed about 1000m before the signal. The latter consists of a rectangular reflective board with alternate black and yellow diagonal stripes.

sighting board

Siding Indicator : A yellow circular board of about 1m diameter, with an 'S' on it indicates facing points for a a siding that necessitate slowing down to a speed below the normal sanctioned speed for the section; the train is required to reduce its speed to 50km/h or less (a speed limit board may be provided as well) and to follow any additional caution or other restrictions after the points which follow. This marker is normally provided only for siding points outside station limits.

Speed Indicators : Rectangular boards with white and black bands and a number indicating the speed (in km/h) permitted for that particular (short) section of track or over the immediately following stretches of points, or temporarily placed just before permanent way work. Usually these signs are placed 100m before the actual spot where the work is being done, or the track has some defect or restrictive condition.

Distance markers : A small slab or board close to the ground, with black letters on white, is the usual form of a kilometer marker. E.g., '96 km'. Indicates the distance to the next major station, or divisional HQ. Intermediate distance markers take the form of a white pole or board on which the kilometer number appears on top, and the number of meters (e.g., '300') below it.

Trackside pole markers : Telegraph or telephone poles, catenary masts, and other repeatedly occurring vertical structures usually have a distance indication painted on, of the form '32/4'; this example indicates the 4th pole after the 32nd kilometer mark. The number of poles or structures within a kilometer's stretch is variable, but usually 16 or 15.

Stop Warning boards : Rectangular warning boards are provided about 1.4km to the rear of a stop signal to warn a driver of the approach to the signal.

Approach to flag station A black dot or small disc in the centre of a square or rectangular (longer side vertical) white board is a pre-warning sign that advises the driver of a flag station or halt station coming up ahead. Such stations don't have any signals of their own.

Coasting Indicator : 'C', black/blue on a yellow diamond shaped board, sometimes a hexagonal board. This is an indication for coasting -- advice to the driver that power can be reduced and booked speed maintained ahead (usually involves switching the traction motors from series to parallel settings). Usually seen on suburban sections with EMU traffic, and usually on sections with a slight down gradient. This is a measure to save on power consumption.

Power Indicator : 'P' red, sometimes black or blue, on a yellow diamond shaped board (sometimes on a hexagonal board). Advice to the driver to increase the applied power (by moving the traction motors from parallel to series settings) in order to maintain booked speed. Usually seen on suburban sections with EMU traffic.

Indication Boards : These rectangular boards indicate changes to signalling systems or block working, or contain other information about signals, etc. Text is usually black on white or black on yellow. On approach to 2-aspect territory without a warner to the rear of a stop signal from multiple-aspect territory or 2-aspect territory with warners, a board with alternate black and yellow stripes and the words 'Approach unwarned stop signal' is provided (1.4km to the rear of the stop signal). On entering single line token territory from tokenless or double line sections, a board with the words, 'Entering token territory' is provided.

Similarly, when moving between automatic block territory and manually worked block territory, indications such as 'Entering absolute block territory' and 'Entering automatic block territory' are provided (placed near or on the same post as the first stop signal). For delayed signals which require a train to stop before they clear, a board may say, 'Driver to pull up to signal if it is at on' or something similar. The stop position for a signal may be indicated by a board that says 'Stop here when signal is on' or something similar.

Shunting limits A rectangular yellow board with a black cross at the top and the words 'Shunting Limit' (or 'S/L') indicates the end of a shunting section. This sign normally also has black and white bands on it, and white lamps attached on both sides (although the words are only on the side towards the station). This is usually provided at class 'B' stations on single-line sections (sometimes double-line) where shunting is permitted on the block section and advanced starters are not provided.

shunting limit indicator

The sign is placed 400m to the rear of the first stop signal of the station in lower-quadrant signalling (180m in modified lower-quadrant, upper-quadrant, and MACL systems). A single white lamp may appear through a hole in the sign above the centre.

Block Limits For stations (usually class 'B') on double line sections in absolute block or automatic block territory (and usually with modified lower-quadrant, upper-quadrant, or MACL signalling) a square or rectangular yellow sign with two intersecting black diagonal stripes, and with the words 'Block Section Limit' is provided 180m in advance of the Home signal; it marks the fouling point of the rearmost trailing points connecting to the station. The acronym 'BSL' may appear instead. The legend faces the station. A single white lamp may appear within the sign through a hole in the sign above the centre.

block limit board

Boards indicating jurisdictional limits of the permanent way for zones, divisions, etc. usually have the codes for the governing stations of the areas on either side of the border.

BB DIVN. - BSL DIVN. indicates the boundary between the Bombay and Bhusaval divisions
DEN/BB - DEN/BSL indicates the boundary between the jurisdiction of the Divisional Engineers for Bombay and Bhusawal divisions. (DEN = Divisional Engineer)
AEN/TNA - AEN/KYN indicates the boundary between the Thane and Kalyan sub-divisions. (AEN = Assistant Engineer)
PWI/TNA - PWI/KYN indicates the boundary between the permanent way inspection sections under Thane and Kalyan

At a divisional boundary, all 4 of the above types of indications are provided; at a sub-divisional boundary, just the AEN and PWI indications are provided. At the ends of sections, just the PWI indications are provided.

Gang Beats are smaller than sections - see below for how these are indicated.

Points Identifier : Electrically operated points are often provided with a small board or slab at ground level with an identifying number (e.g., '56B') in black on yellow.

Points warnings : In advance and to the rear of spring-loaded points controlling slip sidings or catch sidings, warning boards are provided which say 'Spring Loaded Points No Backing' (or similar).

Telephone or equipment marker : A vertical pole, about 1.5m tall, with alternate broad black and white horizontal bands indicates the presence of a lineside telephone or other communication or signalling equipment.

Bridge or culvert marker : Ground-level slab, or small board, with a number and an arrow pointing to the left or right indicates the identifying number for a bridge or culvert. Black on white. Sometimes the number and arrow are painted directly on the bridge or associated structures.

Water level markers : On railway bridge piers, culverts, canal embankments, and other structures, one may find marks indicating high water levels. 'DL' or Danger Level indicates a flood level at which scouring of piers is a concern and necessitates observations and scour measurements as well as possible restrictions on traffic and permitted speed. The danger level is determined based on the type of river (perennial alluvial rivers being more of a problem), the type of the bridge and its spans, the flow velocity, etc. 'HFL' or High Flood Level indicates the level of the highest known flood level recorded at that location. For canal bridges, 'FSL' is the Full Supply Level, i.e., the designed maximum capacity level of the canal.

Pedestrian crossing indicator : A stout pole or slab, about 1.5m high, painted white with numerous thin black diagonal stripes, usually with a tapering top, indicates an area where pedestrians commonly cross the track, although there is no official level crossing at that point.

Telephone indicator : An icon of a telephone handset (black on yellow) with a small horizontal arrow indicates the direction towards the nearest lineside telephone or other communication device for use by drivers or other staff if needed. These signs usually appear on the catenary masts, at about waist level.

Curve Information signs are small white boards close to the ground, with black text indicating the identifying number, turning radius, superelevation, and other such details of a curve in the track. One such board appears at either end of a curve.

Catenary Termination boards are rectangular boards with white or black text on red (or red on white, or sometimes black on yellow) that says 'Electric engines STOP here'. These appear high on the catenary mast, and indicate the absence of the OHE beyond that point, with obvious unhappy consequences for an electric loco that strays beyond. Sometimes only a branch line is unelectrified, in which case the board may say something like 'Caution Unwired Turnouts' (black on red or yellow).

Catenary Signs Boards placed high on catenary masts with (usually black on white) symbols such as a diamond outline, a cross, and a vertical line with two breaks in it. These indicate the neutral sections.

The diamond outline often has a distance ('500m') marking in it indicating the distance to the neutral section. (Sometimes a warning sign such as 'Dead Zone Ahead' (black on white) is also seen.) Usually one such sign is provided 500m before the neutral section and another 250m before the neutral section. At the sign 500m before the neutral section, the loco is powered down by bringing the notch lever down to 0. The driver is also supposed to start switching off the blowers and other auxiliary equipment. By the time the sign 250m before the neutral section is reached (just 10-15 seconds later at typical speeds), all the auxiliary equipment should be switched off, although this is not always true. The older signs are black on white. Newer signs with reflective paint are now in use [1/05] in some places. The 500m sign in the newer scheme is blue with white letters and a white diamond symbol; the 250m sign is white with red letters and diamond.

A cross figure (with the vertical bar broken and not touching the horizontal bar) is the sign just before the neutral section advising the driver to open the DJ (main circuit breaker) for the loco. This is mandatory if the sign is on a post with a white or yellow base. Older signs of this type black on white; newer ones with reflective paint are white on blue.

Immediately after the neutral section a sign with a vertical bar broken at two points is displayed. This advises the driver to close the DJ (BLDJ closed while depressing BLDJR switch simultaneously to close the main circuit breaker) and turn on the auxiliary equipment. Again, the older ones are black on white while the newer ones are white on blue.

Sometimes instead of explicit graphics depicting the pantograph being raised or lowered, three vertical bars one above the other with the middle one displaced sideways from the other two are shown as instructions to raise or lower pantographs before the neutral section. These are mandatory if posted on yellow or white bases.

All these figures are black on white. Any of these may appear more than once near a neutral section, once in plain (unannotated) form for normal trains, and additional signs annotated with the word 'EMU' or 'MEMU' specifically for multiple-unit trains.

neutral section warning boards

 

pantograph raise and lower boards

In the sections where the traction power switches from AC to DC (such as near Virar), a large 'A' on the OHE mast indicates the AC catenary section, whereas a large 'D' indicates a DC catenary section. Additionally, graphic symbols showing a pantograph and an upward or downward arrow warn the driver to raise or lower the pantograph.

pantograph signs near virar

Unexplained sign #1 Near the top of the catenary mast, a square board with a circle in it; within the circle 'B', a red disk, and 'T' in a vertical line. Perhaps something to do with the provision of booster transformers??

Unexplained sign #2 Near the top of the catenary mast, a square board with a blue disk, and the word 'MEMU' on it. This is thought to be an instruction to MEMU drivers to close the DJ -- since MEMU rakes can have more than two pantographs, it can be difficult for the driver to tell when the last one has passed the neutral section.

Track Information Information about a section of track may appear painted on the inside of the rails, or on a small board at ground level near the tracks. Usually the information is concise: for instance, 'CS 52kg IRS laid 15.2.99' which indicates the rail weight, sleepers (CS = concrete sleepers), and the date the section of track was laid. Successive sections of track are often identified by small ground level signs by the side of the track (often, these signs are merely pieces of rail buried in the ground), with labels such as '1 SE85'.

A small white board or slab at ground level may provide an identifying number for a section of track, especially turnouts at points, along with some information about the track (rail weight, date laid, etc.). E.g., 'G21A CS 52kg 1 in 12' which refers to 52kg rails laid with concrete sleepers (CS) for a 1 in 12 turnout.

Welded Rail Information signs are small yellow boards close to the ground, with black text indicating the kind of welded rail section ('LWR No. 13', or 'CWR No. 32', for instance), and the distance marker (km), length of section, date laid, date of destressing and neutral temperature, and other such details.

Gang beats (or beat sections) -- sections of track to be inspected by particular crews of gangmen -- are numbered with 'G' and a number. Thus, one may see a sign that shows:

G-2G-3
1+1+141+1+13

at the boundary between adjacent gang beats, which indicates the sections of track that the gang beats include.

Defect indications There are a large number of standard and ad hoc signs and indications used by permanent way workers to mark defects in track. Many of those that relate to track geometry or ballasting are found on the sleepers or the rails themselves.

C-1, C-2Cross level problem across the two rails - usually indicated on the sleeper inside the gauge
H or P Loose packing of ballast, usually indicated on the sleeper outside the gauge
O+, O- Gauge adjustment needed, usually indicated on the sleeper outside the gauge
Arrows --> <-- Unevenness, twist or curvature problems, usually indicated on the rail web on the face outside the gauge
Arrows pointing up or downFor alignment problems, usually on the on the foot of the rail inside the gauge

If the problem is severe enough to require a speed restriction or caution notices, usually a yellow board is erected with appropriate instructions, e.g., 'XL Defect' to indicate a cross-level defect (subsidence of one rail relative to the other).

Miscellaneous Instructions A large number of signs are used to provide instructions to train crew, permanent way staff, etc. E.g., '1st Engine stop here', 'TTM DO NOT PACK HERE' (instruction to tie-tamping machine operator not to tamp), 'Clearance to OHE nearby restricted' (catenary lower than usual because of bridges or other superstructures), etc. Traffic blocks of different kinds are often indicated on square or rectangular white boards, using black text; often the text is within a black diamond. E.g., 'POWER BLOCK' indicating the OHE ahead is not energized. There may information on the dates/times of the traffic blocks as well.

Lineside hand signals (red or green flags), or banner signals (flags placed at a lineside location temporarily) may be used in instances where the normal signals are out of order, or where maintenance or repair work is going on and traffic has to be controlled overriding the normal signals. See below for information on hand signals. Red banner flags are also placed across the tracks in cases of track-work requiring all trains to halt. Caution signals with a restricted speed indication may also be used temporarily near spots where repair or maintenance is going on, as may Termination indications (T/P, T/G). At night these are replaced by hand-held lamps (red, green, etc.).

Inspection trolley Though not really a sign, included here for completeness. A trolley carries one or two red flags at all times when it is on any section of track

trolley

Hand Signals - flags, lamps, bells, and whistles

Hand signals include signals given by hand, or by flags or lamps used by the signalman, drivers, guards, or station staff.

At most stations and signalbox cabins, it is still customary to use hand-held flags (green and red) to signal trains. In many cases these confirm the semaphore or colour-light signals, but can be used to override them. At night hand-held lamps (red or green) are used instead. The all-right signal refers to the display of green flags by station masters (or other staff), lineside workers, level crossing gatekeepers, and others, to passing trains, or for the driver of one train to another passing train (see drivers' signals below), or from the signal cabin to the driver or guard of a passing train. It indicates a few different things. For trains passing stations, it is a confirmation that the train is allowed to be passing through as the semaphore or colour light signal indicates. The station staff person also keeps a watch for problems such as hot axles, derailed bogies or dragging equipment, or parted couplers, and the green flag indicates there are no such problems observed. Customarily, the green flag is held in the left hand, and the red flag is kept ready to be displayed in case of a problem in the right hand - the custom arose from the idea that the right hand is usually the more vigorous one for most people and the red danger signal could be shown more promptly in case of a problem.

Other hand signals: When a train is to leave a station, a once common practice was for a bell to be rung (6 to 8 beats) by the station master or other station official. The guard would also blow on a whistle. These practices are now sporadic.

On the SER, 6 beats of the bell were used for a down train, and 8 for an up train. On WR, from Vaitarna onwards 3 beats of the bell indicated the EMU train had left the previous station but one, while 5 indicated it had just left the previous station, for trains going away from Mumbai. For trains towards Mumbai, the beats would be sounded with an extra pause.

When a train is about to start moving, normal practice is for the guard to show a green flag or lamp upon seeing the green flag or lamp from the station official, or hearing the bell rung on the platform. (See the all-ready signal in the hand signals below.) The guard's indication is confirmed and repeated by the assistant driver showing a green flag or lamp.

On EMU and other urban/suburban services, often this is dispensed with because it is difficult to sight the guard's flag or lamp over a crowded platform, and also because often EMU services have only a lone motorman in the cab (clearances are also smaller, making it more dangerous in an EMU for any crew member to be looking out of the cab from the side window). Instead, there is a bell and lamp system connecting the guard to the motorman's cabin; two rings of the bell and the lighting of two red lamps in the cabin indicate to the motorman that the guard has given the all-clear for the train to start. This is actually part of a prescribed bell code that is in use in some areas:

  • 1 ring : Stop train
  • 2 rings : Start train
  • 2 rings, pause, 2 rings : Passing automatic signal at 'On'
  • 3 rings : Driver calling the guard to the cab
  • 4 rings : Train protected in the rear
  • 1 ring, pause, 1 ring : Speed restriction zone over, resume speed
  • 3 rings, pause, 3 rings : Motorman not to exceed prescribed speed limit

For all of these, the acknowledgement consists of repeating the same bell signal.

Driver's Signals

It used to be a universal practice for the assistant drivers (or drivers) of trains going in opposite directions to display green flags (green lamps at night) to each other to indicate clear sections further ahead (except for EMU trains in most cases). (The 'all-right' signals, also referred to above.) This practice had become somewhat less common in many regions, although it now appears to be getting revived . Newer locos come equipped with large green/red signal lamps to allow the all-right signals to be exchanged without exposing any of the running staff to the elements. The driver also signals the guard using various whistle or horn codes as mentioned below.

Guard's signals

If there is a problem with the train that the guard has detected, he uses a red flag or lamp to signal a problem. If the guard's van is equipped with side-lamps, they can also be turned to show a red light towards the locomotive. The assistant driver of the train, among his other duties, is expected to keep looking back at the guard's cabin when possible to detect such an indication promptly. The train is brought to a halt when the guard's red signal is seen.

A steady green signal shown by the guard is an indication that there is no problem (or no longer any problem) and that the train can continue on its journey. A green flag or lamp waved violently up and down, however, is the signal that the train has parted, and the driver should bring his portion of the train to a halt. In addition, the guard may also use applications of his hand-brake, or of the continuous braking system if provided, to signal to the driver that the train needs to be brought to a halt for an emergency reason. (Today crew are often assigned walkie-talkies, so that the communication between guard and drivers is often more reliable.)

Lineside hand signals

A red flag, or arms raised above the head, or a red lamp at night (or a white light waved very quickly at night if a red lamp is not available) is the signal for Stop. A green flag held steadily, or one arm extended to the side, or a green lamp held steadily at night, is the signal for Proceed. A green flag waved up and down, one arm to the side moved up and down, or a green lamp at night moved up and down, is the signal for Caution. A train is to reduce speed further if the hand signal becomes progressively slower.

All-ready signal

The all-ready signal is given to indicate that the everything is ready and in order for the train movement for which it is given. It is given by 3 quick waves a green flag horizontally followed by 2 quick waves vertically; at night, waves of a green lamp are used in similar fashion.

Shunting

For shunting, a Stop signal is given as above. A green lamp or flag moved up and down, or one arm moved up and down, is the indication to proceed slowly away from the person signalling. A green lamp or flag moved sideways, or one arm moved sideways across the body, is the indication to proceed slowly towards the person signalling. A green and red flag held together over the head, or both arms above the head and moved towards and away from each other, or a green lamp held above the head and swung by the wrist at night, is the indication to move slowly for coupling.

Whistle and horn codes

Q. What are some of the whistle / horn codes used for communication between the crew of a train and with the ground staff?

Whistle or horn codes consists of long and short blasts on the engine whistle. Here is a list of whistle codes. Notation: We use the following symbols to denote different kinds of whistles. Note that many of these are now no longer in use. The long whistle to indicate a train about to leave a station, and the short whistles to indicate light loco movements are the most common ones still in general use.

  • 'o' : denotes a short blast on the horn.
  • '--' : denotes a comparatively long blast on the horn.
  • '-----' : denotes a longer blast on the horn.
  • '----------' : denotes a very long blast on the horn

  • Code [ o ] - Before Starting:
    • Indication to driver of the assisting engine that driver of leading engine is ready to start.
    • Acknowledgement by the driver of the assisting engine.
    • Engine ready to leave yard
    • Engine ready to go to loco yard
    • Light loco or shunter about to move
  • Code [ o ] - On the run:
    • Assistance of other engine not required
    • Acknowledgement by driver of the assisting engine
  • Code [ -- ]
    • Normal departure from station on receipt of clear signal. This is usually followed by another long blast about 10-20 seconds after the first one, after the guard's all-right signal is received.
    • Beginning of shunting operation (if shunted rake has passengers in it)
  • Code [ o o ]
    • Call for guard's signal
    • Signals not exchanged by guard
    • Signals not exchanged by station staff
  • Code [ -- o ]
    • Guard to release brakes
    • Before starting engine from a mid section/station
    • Main Line clear
  • Code [ o o o ]
    • Guard to apply brakes
    • Train out of control, guard to assist
  • Code [ o o -- ]
    • Sudden loss of brake pressure or vacuum (perhaps by alarm chain being pulled)
  • Code [ o o o o ]
    • Train cannot proceed on account of accident, failure or other cause
    • Protect train in rear
  • Code [ -- -- o o ]
    • Call for guard to come to engine
  • Code [ o -- o ]
    • Token not received
    • Token missed
    • With wrong au thority to proceed
    • Passing stop signal at 'on' on proper authority
  • Code [ ----- ] - Before Starting
    • Vacuum recreated on ghat section, remove sprags
    • Passing automatic 'stop' signal at 'On'
  • Code [ ----- ] - On the run
    • Acknowledgement of guards signal
  • Code [ ---------- ]
    • Approaching level crossing or tunnel area
    • Recall staff protecting train in rear
    • Material train ready to leave
    • Running through a station
    • Approaching a stop signal at 'on'
    • Detained at stop signal
    • Crossing stop signal at 'on' after waiting the stipulated time.
  • Code [ -- o -- o ]
    • Alarm chain pulled
    • Insufficient vacuum in engine
    • Guard applies vacuum brakes.
  • Code [ -- -- ]
    • Raise Pantograph (electric loco only)
  • Code [ -- o -- ]
    • Lower Pantograph (electric loco only)
  • Code [ o o o o o o o o o ] (Frequently)
    • Apprehension of danger
    • Danger signal to driver of an approaching train whose path is obstructed
    • Moving in wrong direction on a double line.
    • Also used by EMU motormen to warn passengers on a crowded platform of the approach of a fast train which will not stop at that station

Signal Defects

Signal Defect Code List


'S' -- Signal Department

S.M.Signal Maintenance inefficient
S.E.Signal equipment - Defective design, manufacture or excessive wear
S.I.Signal Installation incorrect.
S.O.Signal - other failures.

'O' -- Operating Department

O.W.Operating -- Wrong Manipulation
O.T.Operating -- Token Exhausted
O.P.Operating -- Points obstructed.
O.L.Operating -- Lighting Improper
O.H.Operating -- Hanging Coupling etc.
O.I.Operating -- Information not given.
O.N.Operating -- No Fault Found.
O.O.Operating -- Other Failures

'R' -- Running Department

R.C.Running -- Cinder dropped in unauthorised places
R.M.Running -- Missed Token
R.O.Running -- Other Failures

'E' -- Engineering Department

E.C.Engineering -- Creep
E.D.Engineering -- Drainage Inadequate
E.S.Engineering -- Staff Working
E.P.Engineering -- Packing
E.T.Engineering -- Trolley Uninsulated
E.O.Engineering -- Other acts of employees of this department

'L' -- Electrical Department

L.P.Electrical -- Power supply failure
L.F.Electrical -- Fluctuation in voltage
L.O.Electrical -- Other acts of the employees of this department.

'P' -- Posts and Telegraph Department

P.T.P&T -- Theft of Line Wire.
P.C.P&T -- Contact on Line
P.B.P&T -- Break on Line
P.E.P&T -- Earth on Line
P.P.P&T -- party working on Line
P.I.P&T -- Insulation Imperfect
P.L.P&T -- Leakage of extraneous current
P.O.P&T -- Other acts of employees of this Department.

'M' -- Miscreants

M.T.Thefts
M.D.Damages
M.I.Interference

'X' -- Other Classification

X.WWeather extremes like storms etc.
X.X.Unknown, cause not established
X.F.Fire
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