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 (class of train) :
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)
0 = Locomotive(s) only. Up to 5 locomotives being moved on their own. 6 to 10 locomotives coupled run as a Class 6 train
Note : Freight traffic uses different classes based on maximum permitted speed of the wagons. If the wagons being conveyed permit the train to travel at a different speed compared with the booked Class of train the headcode used will change e.g. from 6A01 to 4A01 or 7A01. If no wagons are being conveyed the Class will change to 0.
Second digit
A letter which signifies the destination area of an inter-regional working, or a route or zone within the historical railway region (Scotland, London Midland, Eastern, Anglia, Southern, and Western).
Trains from one region to another region would utilise the letter for the region where the train terminated.
S = Scotland;
M = London Midland;
E = Eastern;
L = Anglia;
O = Southern;
V = Western.
More recently some inter-regional routes now utilise a specific letter for a regular route e.g. F = Portsmouth / Bristol / Cardiff trains.
Other letters used throughout the network for some trains.
Q = Test trains, New trains being tested, Some maintenance movements between depots etc.
X = Trains with restrictions on route/lines to be used because of gauging (shape/size of train and load) considerations passing various structures (e.g. bridges, tunnels, station platforms and canopies)
Z = Special workings often used for engineering works alterations or at times of disruption (London Midland also use T and Eastern also use G)
Within each region other letter are used for internal to the region. Letters can be used more than once regionally for trains that operate in different areas.
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 ways)
....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 morning peak Avanti 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 customers 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.
Since July 2022 Railcam has had access to the correct freight headcodes and these are now displayed.
On Track Machinery (Tamping Machines, Rail Grinders, Mobile Maintenance Trains etc.)
Most machines have their own headcode which will readily identify the machine. These are usually 6Jnn, 6Unn and 6Qnn. Railcam usually auto-allocates the machine against the headcode but occasionally this can result in a machine appearing to have been allocated on a freight train as a few freight trains run with a 6Jnn headcode that duplicates that of the machine.
Signaller Messages and codes
Apart from headcodes, as detailed above, berths may sometimes contain other codes, which have been placed there by a signaller. Here are some of the codes you may see. This is not a complete list and may vary slightly dependent on how the inputter decides to abbreviate a word. Sometimes more than one berth may be used and if the signallers diagram shows the other way round the 'message' may read backwards.
.*X** or **** = Train describer showing section occupied without a headcode. Can be a fault or equipment on track during engineering work.
NOGO = a reminder not to use a particular route
FAIL = a failed signalling section or train
SHUT = indicates a closed section of line - perhaps a closed signalbox
-LB- = Short term line blockage (closure) for staff safety during track or train examination
-T3- = total (long term) engineers possession (will often be accompanied by ITEM and a number referring to the applicable Engineering Notice for the work which may be abbreviated to something like I321. DETS may appear at the outer ends of the area indcating relative position of the detonator protection for the engineering work. KEYD may appear at ends of of the engineering works indicating an automatic signal keyed to danger to provide protection for the area, an example of the key switch can be seen at http://www.fourbythree.co.uk/library/large/sig/SPRS-1.JPG ).
BTET = Blocked To Electric Traction indicating a problem affecting the electric traction supply but still available for non-electric trains.
-RT- and 3187 = Title of the form in connection with a signalling disconnection usually associated with long term alterations in an area.
TEST = If a signaller needs to test the Train Describer equipment, it will be done by placing TEST in a berth.
-nnn = A number to give some indication of a berthed unit number (may utilise two berths) usually found in a terminal platform berth.
Colour coding
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. Because of the format of certain freeform entries occasionally a 'wrong' colour will show for an entry.
White = A normal scheduled passenger train
Blue = A passenger train which is not in the normal published 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
Orange = A train to assist in reopening the railway. e.g. an assisting locomotive for a failed train or a snowplough or similar. These movements are usually unscheduled.
