Train reporting number

Headcodes were introduced around 1850 and were shown by oil lamps facing forward on the front of the locomotive. The position of these lamps on the locomotive denoted the class of train, which assisted the signalmen to determine the gaps between trains required in the interval-based signalling system that was used at the time. The lamps were lit at night and were usually painted white to assist with sighting by day. On some lines white discs were used by day in the place of lamps.[1]

With the coming of absolute block signalling, the class-based headcodes allowed signallers to identify and regulate trains properly. However on some busy lines, particularly busy suburban ones, the headcode denoted the route of the train rather than the class of train. In these areas junctions were complex and timetables were intense: it was more important that signallers routed the trains correctly than regulated trains by class. This was prevalent in the south of England, where companies used six headlamp positions to show the route of train.[1]

Some companies had their own code format which led to some confusion where trains from one company ran onto other companies' lines. The Railway Clearing House intervened to standardise headcodes, based on four lamp positions, and they were adopted by the majority of lines outside the south of England. At the time of the 1923 Grouping, the standard headcodes were simplified so that normally only two lamps were used at any one time, and these codes were adopted by the London Midland and Scottish Railway, the Great Western Railway (GWR) and the London and North Eastern Railway. The Southern Railway (SR) retained a route-based headcode system, with up to four lamps in six positions. Notable exceptions were former Glasgow and South Western Railway and the Somerset and Dorset Joint Railway lines, which continued with their own headcodes on internal trains.[1] The Caledonian Railway maintained a completely different route-based headcode system consisting of a pair of semaphore arms mounted on the locomotive - the angle of the two arms and their position (on the buffer beam or smokebox) indicated the routing.[2]

Southern Region electric multiple units showed two-character headcodes, where the code denoted the route of the train

Great Western Railway Cornish Riviera Express with three digit number on the locomotive smokebox

Historically train reporting numbers were used to denote trains in the internal working timetable. These contained one or more letters or numbers to either uniquely identify a particular train, or denote its route (particularly on busier lines). Not all lines used these and the details and extent of the practice varied widely between companies. Although these numbers were in many places confined to timetables and other documentation, in some busier areas they were actually shown at the head of the train.

On the SR, a single alphabetic character system of denoting routes used on suburban lines grew into a two character route-based system. This was developed at the same time as a significant programme of electrification and the consequent introduction of a large number of multiple unit trains. Many of these trains were fitted with display devices to show the route code instead of a lamp or disc-based headcode. Originally this was a back-lit stencil with the single letter code, later a two-character roller-blind system was used. The code system had equivalence with the lamp or disc route-based headcodes in assisting signallers with routing trains.

On the other railways, the reporting number was on occasion displayed at the head of the train along with the lamp headcode. This happened more often than not with special trains or other unusual trains (e.g. summer Saturday timetables), to allow signallers to identify unfamiliar trains and route them correctly. This code was sometimes either chalked onto the locomotive front or pasted as paper characters onto a headcode disc. The GWR sometimes used a three-character frame mounted on the locomotive smokebox in which the train reporting number could be displayed.[1]

After nationalisation, British Railways continued with these headcodes and the new diesel and electric locomotives and multiple units were built either with a disc/lamp system (now powered by electricity) or a two to four character roller-blind display system depending on what part of the network they were to work.[1]

A Class 47 locomotive displaying headcode 0000 in 1976

In 1960, the current format was introduced where train class, route and reporting number information are combined in four characters. All diesel and electric locomotives and multiple units built after that date were fitted with a roller-blind display that could display the full reporting number, except locomotives and multiple units destined for the Southern Region, which continued its long-standing practice of two-character alpha-numeric displays.[1]

By 1976, the replacement of the huge number of manual signal boxes with centralised power-signalling coupled with computer-based train control and more modern telecommunications systems meant that it was no longer necessary to display headcodes throughout the railway network. Outside the Southern Region blinds were set to 00 or 0000, and discs/lamps to the former express passenger code. Roller blinds were later blanked or plated over to show two dots and new trains introduced for service outside the Southern Region after this time usually had no train reporting number display equipment.[1] Many trains intended to run over Southern Region lines were designed to display the numeric route-code portion of the train reporting number, which they still display, usually as a dot-matrix display.

Class 37 locomotive with its headcode panel converted to two marker lights

For operational reasons, certain trains have priority in running. To help operating staff, they are grouped into classes; these were formerly identified using letters. When the letter groups were replaced by numerals on 18 June 1962, the classifications became:[3]

1. (formerly A) Express passenger, newspaper, or breakdown train; express diesel car; snow plough on duty; light engine proceeding to assist disabled train.
2. (B) Ordinary passenger, branch passenger or "mixed" train; rail motor (loaded or empty); ordinary passenger or parcels diesel car; breakdown train not on duty.
3. (C) Parcels, fish, fruit, livestock, milk or other perishable train composed entirely of vehicles conforming to coaching stock requirements; empty coaching stock (not specially authorised to carry Class A [sic] code).
4. (C) Express freight, livestock, perishable or ballast train pipe-fitted throughout with the automatic vacuum brake operative on 90 per cent of the vehicles.
5. (D) Express freight, livestock, perishable or ballast train with not less than 50 per cent vacuum braked vehicles piped to the engine.
6. (E) Express freight, livestock, perishable or ballast train with 20 per cent vacuum braked vehicles piped to the engine.
7. (F) Express freight, livestock, or ballast train not fitted with continuous brake.
8. (H) Through freight or ballast trains not running under C, D, E or F [sic] conditions.
9. (J) Mineral or empty wagon train.
   (K) Pick-up branch freight, mineral or ballast train.
0. (G) Light engine(s) with not more than two brake vans.

The classes are periodically revised, and since 13 December 2017, the classes have been:[4]

1. Express passenger train; nominated postal or parcels train; breakdown or overhead line equipment train going to clear the line (headcode 1Z99); traction unit going to assist a failed train (1Z99); snow plough going to clear the line (1Z99)
2. Ordinary passenger train; Officers' special train (2Z01)
3. Freight train if specially authorised; a parcels train; autumn-railhead treatment train; empty coaching stock train if specially authorised
4. Freight train which can run up to 75 mph (120 km/h)
5. Empty coaching stock train
6. Freight train which can run up to 60 mph (95 km/h)
7. Freight train which can run up to 45 mph (70 km/h)
8. Freight train which can run up to 35 mph (55 km/h)
9. Class 373 train; other passenger train if specially authorised
0. Light locomotive or locomotives

For long distance trains, the country is split up into areas based upon the old British Rail regions. Each one is assigned a letter as follows:

• E: Eastern
• L: Anglia
• M: Midland
• O: Southern
• S: Scotland
• V: Western

A train going from one region to another is given the letter of the destination region in its headcode. Prior to 1967 N was used to signify trains destined for the erstwhile North Eastern region.

For trains internal to a region, the remaining letters can be used to indicate either:

• A destination zone inside that region, or
• A route within that region.

Some areas within the Midland region are:

• A: London Euston or London Marylebone
• D: North Wales
• G: Birmingham
• H: Manchester
• C: London St Pancras (via Derby)
• D: London St Pancras (via Nottingham)
• F: Liverpool
• C: Cumbrian coast and Windermere

While on the Western:

• A: London
• L: London (on services from Cardiff and Swansea)
• B: South Wales (e.g. Cardiff or Swansea)
• C: Bristol and West of Bristol (e.g. Exeter, Plymouth or Penzance)
• F: Cardiff to South coast of England and return

Examples from the Scottish Region include

• A: Aberdeen
• B: Edinburgh
• G: Fife, including Fife circle via Dumfermline, and Longannet Power station
• H: Inverness
• I/O: Cathcart Inner/Outer circle respectively
• R: Express services between Glasgow Queen Street and Edinburgh (even numbers eastbound, odd numbers westbound)
• T: Glasgow (trains from the north)
• Y: West Highland

Other regions can use these letters for different areas, but the inter-regional codes have the same meaning throughout the country.

In 2007, a special letter Q was introduced for track recording trains, such as the Network Rail New Measurement Train. This emphasises to signallers that the train is to run its booked route as it is recording, not to be diverted without the prior knowledge of the controller. Prior to this, trains operated by British Rail Research Division used the letter T.[5]

The letters X and Z are generally reserved for special use – see below.

Because there are many trains of the same type heading for similar destinations (for example, most expresses to Scotland have headcodes beginning with 1S) the last two digits are used to separate individual services or to indicate the route (generally for suburban services).