Return to index page

Bell Codes & Locomotive Head Codes

Signal Box Bell Codes

Larger layouts often need several people to operate them and the use of bell codes is both authentic and useful for advising the next operator on the line what you are sending to him. The following are some of the bell codes used for different types of train by BR that may be of use on a layout. These codes relate to "Headcodes", a distinctive arrangement of lamps or disks on the front of the locomotive indicating the type of train it is pulling. Headcodes are discussed in more detail below:


1-2 Branch line train

1-2-2 Express freight, livestock or fruit train with a substantial proportion of vacuum braked stock.

1-3-1 Non-passenger coaching stock (parcels, fish or fruit vans, fitted livestock vehicles or milk tanks/vans)

3-1-1 Express freight, livestock, perishable or ballast train with at least half the vehicles fitted with automatic brakes

3-2 Express freight, livestock, perishable or ballast train, not fitted with the automatic brake

5 Express freight, livestock, perishable or ballast train, at least one third being fitted.

3 Freight, mineral or ballast train, stopping at intermediate stations (e.g. the 'pick up goods train)

4-1 Mineral or empty wagon train

1-4 Through freight or ballast train class "H" headcode

3-2-5 Freightliner train


4 Express passenger train or newspaper train (or a breakdown train going to clear the line in this section)

3-1 Ordinary passenger train, mixed train (or breakdown train that is not going to clear the line in this section)

1-3 Branch passenger train

3-1-3 Diesel rail bus

2-2-1 Empty coaching stock

Light Engine

2-3 Light Engine

2-1-3 Light engine has arrived

Useful additional signals

1 Attention (*see below)

2 Train now entering section on its way to you

2-1 Train (from you is) now clear of section

1-5-5 Shunt train onto a siding to allow the following train to pass.

6 Obstruction danger.

2-1 Obstruction cleared

6-2 The train has taken an unusually long time in section.

5-5 Train divided, a more likely signal would be:

9 Train heading for you had no tail light on the rear when it passed my box

* The Attention signal is used to confirm that the called box is listening. A single bell is sent to the called box and repeated back to the calling box before each signal is sent. As an example if Box A wishes to pass a light engine to Box B the exchange would be as follows:






  Calling attention



  I am listening



  I have a light engine coming your way



  Okay send me the light engine

Train passes the first signal box (in this case A)



  Calling attention (not reqd see below)



  I am listening (not reqd see below)



  Train entering section



  Okay the train is on its way to me

Train transits the section



  Calling attention



  I am listening



  The train has now cleared the section



  Okay the train has cleared the section

Mike Hodgson was kind enough to point out that in practice the single 'ting' to call attention was not used when the train was entering the section, the reason being that the other signalman would be expecting it as he had already been offered the train. Mike explains:

In the example you show an exchange of the Call Attention signal before sending 2 beat Train Entering Section (TES)
It is not normal practice to do precede TES with call attention – It isn’t required by regulations. Presumably the reason it is considered unnecessary is that the signalman is expecting TES anyway because the train is imminent because it was offered and accepted a short while ago – he will know from the type of train how fast it will be going, so has a pretty good idea of exactly when he expects to hear it.
Similarly of course, he knows when he expects to hear Train Out from the box in advance. With Train out of section, your example is right because the regulations do call for Call attention in that case, and many signalmen invariably follow that procedure. In practice however that exchange of Call Attention has always been dispensed with in some busy boxes – unofficially of course. If there was an inspector about you worked by the book. It is one of a few short-cuts usually known as “sloppy working”, and some inspectors were notorious for trying to catch signalmen doing it. The problem for the signalman of course was that he didn’t necessarily know if the chap at the other end was entertaining management. One discreet way of warning your oppo was to give a long single beat – as the hammer does not fall back this makes a duller flat note on the bell, and is therefore distinguishable from Call Attention. The crafty way to save your mate from having to get up out of his armchair to acknowledge Train Out was to send the single Call Attention beat, but drop the block at the same time. The signalman receiving this would see the needle fall and realise he didn’t need to bother answering. And you wouldn’t bother with the 2-1. But if he happened to have visitors, he would acknowledge the Call Attention, thus putting his mate on notice that he should be following procedures, so they would then exchange the 2-1 signal as per the book.

Single stroke bells had other uses on the railways, the signal box might have a line to a bell at the station so the signalman could warn the station staff of an approaching train. On the train itself the guard communicates with the engine using such a bell, the most familiar signal is the two rings that indicate the train is ready to depart. Less commonly heard is a single bell (which means 'stop'), three bells (move back a bit) and six bells (move forward a bit).

Tail Lights & Locomotive Head-Codes

The Liverpool & Manchester railway introduced a rule that every train must have a light on the rear so the lineside staff could see that no wagons had been left behind in the section, and also (hopefully) to avoid rear-end collisions on the line. Originally these lights were red when moving and blue when stationary. The brake vans attached to trains from the 1850's on carried lights mounted both on the rear and also on the sides. Both these lights showed red to the rear and some of the side lights showed white to the front. When the brake vans disappeared in the 1970's and 1980's a single tail lamp was attached to the rear of the last vehicle in the train. These lights were still the standard white oil lamps with a red lens, electric lights, again with a red lens, appeared in the 1970's and a yellow, flashing, electric rear lamp was introduced in the mid 1980's.

Head codes were shown on the front of the locomotive itself. These appeared in about 1850 and originally consisted of a number of white painted oil lamps which were mounted on brackets fitted to the buffer beam and boiler door of the loco. These codes showed the type of train, express or slow, goods or passenger, and were introduced to help the signal man when the line was being operated on the 'interval' system (described below). The lamps were carried on a set of four brackets fitted to the locomotive buffer beam and boiler door. Most codes required only two lamps to be fitted.

Fig ___ Original RCH Code for Locomotive Lamps

Sketch showing Original RCH Code for Locomotive Lamps

The Railway companies had their own variations on this arrangement, Southern Railway and cross-London trains were fitted with two additional positions on either side of the smoke box door on the front of the boiler to give a total of six positions. Other variations were plain white disks used in place of the oil lamps for day-time working (used by the Southern Railway and London & North Eastern Railway) whilst some companies had numbers or different shapes or colours in place of the white disks. At least one company used a set of small 'semaphore' type signals mounted on the front of the boiler.

At about the time of the 1923 grouping, a new code was evolved, again with four brackets as before but which only required a maximum of two oil lamps.

Fig ___ RCH revised lamp codes

Sketch showing RCH revised lamp codes

The Southern Railway continued to use its own system of five positions and the old Glasgow & South Western and Caledonian lines under LMS ownership did not conform to these national codes for internal working.

Route Indicating Head Codes

The simple indication of train type, although useful for the interval signalling system, was not ideal for traffic reporting purposes. Some lines found it preferable to add an alpha numeric code indicating the service the train was on (i.e. 'this is the 8.15 London to Manchester service'). The Southern Railway and Great Western Railway added their own two character (SR) and three character (GWR) alpha numeric head codes, displayed on metal plates fitted to the front of the locomotive.

British Railways diesel locomotives built before 1961 for the Southern and Western regions of British Railways were often fitted with two and three character headcode boxes to display the special codes used on these lines (inherited from the SR & GWR). The Southern Region Class 33 (as available from Graham Farish) for example displayed the code on a simple roller-blind in the centre cab 'window' and the Western Region 'Warships' (available from Minitrix) originally had a three-character code box built into the nose.

Fig ___ Southern Region and Western Region Codes

Southern Region and Western Region Codes

British Railways used the RCH standard lamp codes and adopted the disks for all locomotives except Diesel Multiple Unit stock. On diesels the lights were electric and were built-in to the ends of the locomotive body, the discs were permanently fitted but could be folded in half (the inside face was white, the 'rear' face of the fold-down upper half was the same colour as the locomotive). The centre two discs were off-set slightly to the right (that is to your left when looking at the front of the locomotive). The two additional lights on either side of the smoke box door were included and on Southern region diesels the two additional positions were fitted with standard British Railways fold down disks. On the DMU's there were two lights fitted low down to either side of the front of the vehicle (rather like headlights on a road vehicle but not as bright), these replicated the passenger train oil-lamp headcode. On the DMU's the lights showed white to the front and red to the rear.

In 1960 the disk system was officially replaced by four-character head-code boxes which displayed the actual diagrammed reference for a particular service. On steam locomotives these four character head codes were displayed using metal plates painted black with code letters and numbers about nine inches to a foot high in white. Diesel locomotives displayed the code in an illuminated box on the locomotive front. As noted above the code displayed was related to the specific diagram the train was working and was intended to assist signalmen in reporting train movements.

The new four character headcodes began to appear in 1961 and the Western Region diesels had their code boxes modified to show four instead of three characters. The Southern Region kept its two character codes for internal workings, and expanded the system to cover all services, but southern locomotives displayed the full four characters when on inter-regional hauls.

On locomotives fitted with doors to allow the crew to move between locomotives when 'double heading' the head code was divided in two, with a two character box to either side of the doors. These doors proved unpopular and were later welded shut, new locomotives were then built with a four character headcode box fitted centrally. The four character codes identify the individual 'diagram' the train is working not just the train type.

Under the original 1960 scheme the first number corresponds in the main to the old oil-lamp train code letters (shown in brackets):

1 (A) express passenger, mail or breakdown train en route to a job.
2 (B) Ordinary passenger or a breakdown train not going to clear the line.
3 (C) Parcels, empty coaching stock or Freightliner train.
4 (C) Express freight train, fully fitted.
5 (D) Express freight with at least a third of fitted stock connected to the locomotive.
6 (E) Express freight with no less than 4 fitted vehicles attached to the locomotive.
7 (F) Express freight, ballast or empty train, unfitted
8 (H) Unfitted through freight or mineral train.
9 (J or K) Mineral or stopping goods train
0 (G) Light engine or engines with or without brake vans.

This was changed in 1968 when steam had gone to:

1 Express passenger or mail, breakdown train en route to a job or a snow plough going to work.
2 Ordinary passenger train or breakdown train not en route to a job
3 Express parcels permitted to run at 90 mph or more
4 Freightliner, parcels or express freight permitted to run at over 70 mph
5 Empty coaching stock
6 Fully fitted block working, express freight, parcels or milk train with max speed 60 mph
7 Express freight, partially fitted with max speed of 45 mph
8 Freight partially fitted max speed 45 mph
9 Unfitted freight (requires authorisation) engineers train which might be required to stop in section.
0 Light engine(s) with or without brake vans

The second character, a letter, indicated the destination of the train. The regions each had their own codes but inter-regional trains use following letters:

E     Train going to       Eastern Region
M         "     "     "         London Midland Region
N         "     "     "         North Eastern Region (disused after 1967)
O         "     "     "         Southern Region
S          "     "     "         Scottish Region
V         "     "     "         Western Region

The last two numbers identified the actual working involved.

In 1976 British Railways decided that these codes were no longer to be displayed on the locomotive and they were all set to read OO OO with the exception of the Western Region Class 50's which had them set to display the locomotive running number. Eventually the code boxes were painted over, some were later used to house a high intensity white headlight intended to help people avoid being run down on the line by the fast moving but quiet diesel and electric trains.

The four character codes, although not displayed on the locomotive, are still in use today to describe specific diagrammed workings.

Go to top of page

International Good Guys ~ Poking fun at bad guys since 1971 ~ Site maintained by Disabled Access to Computing
All material Copyright © Mike Smith 2003 unless otherwise credited