Trackside Prints

Train headcode decoder

Type a headcode, like 1A25 or 6M50. You get the class of train its first number stands for, what the letter and the number are for, and which timetable says so.

Decode a headcode

1V15

PartHereWhat it tells you
First: the class1The kind of train. See below.
Second: the letterVWhere it is going: a destination area or district. Each timetable book sets its own letters, so the same letter means different places in different areas.
Last two: the number15That train's own number, from 00 to 99.

Class 1 in the timetables we read:

  • Express passenger train or mail train (Network Rail WTT books LA and LC)
  • Express passenger train, Royal Mail train or Sandite (Network Rail WTT book LB)

To find what the letter means for your line, look up the area's book in Network Rail's working timetable. Its front pages list the letters under "Four character train identification system".

A maroon Western diesel locomotive with a yellow front panel showing 1V15, leading a train through a wooded cutting on a sunny day
1V15 on the front of a Western diesel on the Severn Valley Railway. Photo of the Severn Valley Railway near Northwood: Gareth James, CC BY-SA 2.0
Every class, 0 to 9, from the timetables we read
First numberMeaningWhere we read it
0Light locomotive(s)Network Rail WTT books LA, LB, LC and LD
1Express passenger train or mail trainNetwork Rail WTT books LA and LC
1Express passenger train, Royal Mail train or SanditeNetwork Rail WTT book LB
2Ordinary passenger trainNetwork Rail WTT books LA, LB and LC
3Empty coaching stock between Paddington and Westbourne Park, or priority empty coaching stock if specially authorisedElizabeth line central section only (RfL(I) CCOS Timetable Planning Rules 2026, table 1-2)
4Freight train permitted to run at more than 60 mphNetwork Rail WTT book LD
5Empty coaching stock trainNetwork Rail WTT books LA, LB and LC
6Freight train permitted to run at 50, 55 or 60 mphNetwork Rail WTT book LD
6Engineering and maintenance trains that can run up to 50 mphElizabeth line central section only (RfL(I) CCOS Timetable Planning Rules 2026, table 1-2)
7Freight train permitted to run at 40 or 45 mphNetwork Rail WTT book LD
8Freight train timed not to exceed 35 mphNetwork Rail WTT book LD
8SanditeNetwork Rail WTT book LA
9International passenger trainNetwork Rail WTT books LA and LB
9Passenger trains on the Crossrail central sectionElizabeth line central section only (RfL(I) CCOS Timetable Planning Rules 2026, table 1-2)

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How to use it

Type the four characters you saw on a departure screen, a train describer or the front of a train. Capitals or not, spaces or not, it reads them. The answer splits the headcode into its three parts and gives the class meanings we found in the timetables.

What the four characters are

A headcode is four characters: a number for the class of train, a letter for where it is going, and a two-digit number, 00 to 99, for the train itself. Rail for London's planning rules for the Elizabeth line set it out that way, with 9W05 as the example (CCOS Timetable Planning Rules 2026, section 1.4.1).

Network Rail's working timetable says the same at the front of each book, under "Four character train identification system" (working timetable). Each book lists the classes and letters used in its own area.

A black steam locomotive numbered 92134 arriving at Goathland past a semaphore signal, people waiting on the platform
92134 arriving at Goathland, on the North Yorkshire Moors Railway. Photo: Gordon Hatton, CC BY-SA 2.0

The first number

In book LD, the freight book for lines from Tottenham to Ely, Norwich and Lowestoft, the first number sorts freight by speed: 4 for trains permitted over 60 mph, 6 for 50, 55 or 60 mph, 7 for 40 or 45 mph, and 8 for trains timed not to exceed 35 mph. The passenger books use 1 for express passenger or mail trains, 2 for ordinary passenger trains and 5 for empty coaching stock. 0 is a light locomotive in all four of the books we checked.

We found no class 3 in the Network Rail books in the June to December 2026 download. So for class 3 we give the Elizabeth line's meaning, and say that is what it is.

The letter changes from place to place

The same letter means different places in different books. In book LA, E is "To East Coast Main Line area". In book LC, E covers empty trains to East Ham depot and trains to the Eastern area, and V is "Great Western area". So we tell you what the letter is for, not where it goes.

Book LC adds a rule for its own lines: trains from London have even numbers and trains to London have odd ones.

Sources: Network Rail working timetable, June to December 2026 download, books LA, LB, LC and LD (front pages; the books' own covers carry 2024 dates, and book LB 2017); Rail for London (Infrastructure) CCOS Timetable Planning Rules 2026, section 1.4.1 and table 1-2. Read 30 October 2026.

Written by Craig Fearn, Trackside Prints. Last updated .

Questions, answered

What does the 1 in a headcode mean?
Class 1: express passenger train or mail train, in Network Rail working timetable books LA and LC.
What does the letter in a headcode mean?
A destination area or district. Each timetable book sets its own letters, so the same letter can mean different places.
What is a class 6 train?
In Network Rail's book LD, a freight train permitted to run at 50, 55 or 60 mph.