Mission codes

Mission codes are train identifiers that convey train's service and information. It was first put into RER C in Paris in 1979. The RATP nomenclature of mission codes was brought to Enchancian passenger railways in 1983. The freight system has its own set of codes.

Information
Each train in the Enchancian railway network is identified by a mission code of four letters and two (in some Enchancian railway networks, three to six) digits. The first letter indicates the terminus of the train, the second characterises the mission of the train i.e. the whole of the points of stop (in case of freight trains, it may be a random letter, or the load of the train), the third and fourth letters supplement the name. For example, in Paris' RER A, trains "ZEBU" have a terminus in Saint-Germain-en-Laye (letter Z) and are omnibus (letter E). The two figures indicate the sequence number of the trains and the direction of circulation - odd for east-west (or south-north), even for west-east (or north-south). Some Enchancian freight railway networks added a third figure after the two figures (indicating the sequence number of the trains and direction of circulation) to indicate if the train was loaded or empty (an odd number is an empty train, an even number is a loaded train). That is the same case for the Helidon City Railways (mission codes in that network consist of the destination (first letter), the stations served by the train (second letter), supplements (third and fourth letters), the sequence number of the trains and the direction of circulation (first and second digits), the train type (third digit or a letter) and sometimes, not always, two letters indicating the line).

Helidon City Railways
Helidon City Railways uses a format of four letters, two digits, one alphanumeric character and two letters (mostly omitted). For example, a train running to Helidon Airport stopping at all stations on the Airport line using the E set will be VELA285.AP.