View source for Headcodes and colour-coding

''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 usually 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 = Originally used for Freight trains capable of more than 75mph but now used for some test trains and some empty passenger trains which have time or route critical paths.

4 = Freight - limited to 75mph 

5 = Empty passenger coaching stock (ECS) 

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 = Originally only Eurostar trains but also now expanded to include certain other workings requiring a specific routing (e.g. West Coast Main Line trains via Birmingham and London Overground trains via East London Line)


'''Second digit'''

A letter which signifies the destination area of an inter-regional working, or a route or zone within the region. By way of example, here are the codes used in the London Midland 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'''
These are the train number and usually sequential. If the same route letter is used for both directions odd numbers will go in one direction and even the other direction.


'''Freight Headcodes on the Diagram'''

Reportedly due to pressure from customers such as the big supermarkets, Network Rail initially excluded 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 "anonymised" the headcodes so that the train cannot be immediately identified. Since then, GBRf have apparently opted-out of the scrambling system. The Railcam system also allows users to add the "true" headcode to a particular train, so that it will display correctly on the diagrams that day.

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.

'''Signaller 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.

*X** or **** = 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- = Short term line blockage for staff safety during track or train examination 

-T3- = total (long term) engineers possession 

1TRN =First Train. Used to remind signallers 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 signaller needs to test the Train Describer equipment, it will be done by placing TEST in a berth.


'''Colour coding'''

[[File:Colour Guide.png]]

This picture shows the colours used by Railcam to readily identify different types of trains operating. These colours are unique to this site and are just used so the viewer can pick out trains of interest more easily. 

White = A normal scheduled passenger train 

Blue = A passenger train which is not in the timetable 

Lilac = A locomotive only movement 

Yellow = A freight or test train, also includes some ECS trains (mainly during peak periods) for which timekeeping is critical 

Red = A freeform entry made by the signaller as a reminder. Sometimes this may be across more than one signal berth. Occasionally these may appear in another colour because of the nature of the entry 

Green = A time entered by a signaller as a reminder for when action is required. e.g. train booked to depart or engineering work to finish