Headcodes and colour-coding

Each numbered position on the diagram represents a "Signal Berth" - a portion of track protected by a similarly numbered signal on the actual railway line.

When that Berth is un-occupied, it displays the Berth number.

When it is occupied (or when a signaler uses it to display a note/message), it will show in Yellow.

Headcodes

Headcodes are used to identify a particular train. They are not completely unique and the same identification might be used for multiple trains around the network, but not at the same time. A headcode is a 4-digit (numbers and letters) code, which can be interpreted as follows :

First Digit :

1 = Express passenger service (or postal)

2 = Local passenger service

3 = Freight - capable of more than 75mph

4 = Freight - limited to 75mph

5 = Empty stock working

6 = Freight - limited to 60mph

7 = Freight - limited to 45mph - occasionally used for track machines and departmental 8 = Freight - limited to 35mph or less - occasionally used for track machines and departmental 9 = Eurostar

Second digit

A letter which signifies the destination of an inter-regional working, or a route or zone within the region.

Looking at the first two digits together :

1A = London Euston 2A = Crewe/South Manchester via Manchester Apt 1B = London Euston via Birmingham New Street ....or Blackpool North/York services (both way) ....or Manchester Apt/Sheffield/Cleethorpes services (both ways) ?C = Cumbria/Morecambe ?E = Eastern ?F = Liverpool/Southport/North West ?G = Birmingham area 1H = Manchester Picc/Apt 2H = Leeds to Morecambe (both ways) ....or South Manchester services ?J = Manchester North/Wrexham/Strewsbury ?K = Crewe ?L = Norwich/Cambridge/Stanstead Apt ?M = North West/Midlands inter-regional ?N = Preston/Blackpool North ?O = Southern England Inter-Regional ?P = Preston/Lancaster ?R = Mon-Fri peak hour VT arrivals into London Euston ?S = Scottish Inter-regional ?T = Special/test/retimed trains only ?U = North West England to Manchester South ?V = West of England/South and West Wales inter-regional service ?X = Other special services

The third and fourth digits are a the train number.

Freight Headcodes on the Diagram

Reportedly due to pressure from customers such as the big supermarkets, Network Rail initially exlcluded all freight from the data-feed which the diagram uses. Fortunately, from January 2013, freight has now been added and all services are now represented. However, to keep the freight customerss happy, they have "anonomised" the headcodes so that the train cannot be immediately identified.

Headcodes which have been scrambled in this way, can be identified by their form - three numbers followed by one letter. The first digit of the headcode (train class), remains un-altered, but the following 3 digits are effectively meaningless.

Signaler Messages and codes

Apart from headcodes, as detailed above, berths may sometimes contain other codes, which have been placed there by signalmen. Here are some of the codes you may see.

• • • • = Train describer error

NOGO = a reminder not to use a particular route FAIL = a failed train SHUT = indicates a closed section of line - perhaps a closed signalbox -LB- = emergency / short term line blockage -T3- = total (long term) engineers possession 1TRN =First Train. Used to remind signalers that the next train will be the first over a previous possession or other problem location and care needs to be taken. TEST = If a signaler needs to test the Train Describer equipment, it will be done by placing TEST in a berth.