A station code is a brief, standardised abbreviation, or alphanumeric code, used by railways to identify a railway station uniquely (within a country or region). Codes are mostly used internally but can be seen on railway traffic signs and on some timetables.
In most countries, station codes are purely alphabetic, usually compromising a few capital letters for ease of identification, in some countries one capital and one or some lowercase letters.
Indian Railways uses one- to four-letter codes.[2] Most stations of the Indian Railways are assigned three letter codes, for example, the station code for Mumbai Central station is MMCT and for Guwahati is GHY.[3]
One-letter station codes of the Indian Railways[3]
Unallocated one-letter station codes of the Indian Railways include A, B, C, D, E, F, I, H, K, L, M, N, P, Q, T, U, V, W, X and Z.
Japan
In Japan, alphabetic station codes are not used. Japanese railways use station numbering, a sign system which assigns station codes consisting of a few letters and numbers to train stations.
In Sweden[8] and Denmark, railway stations are assigned a capital letter followed by a sequence of lowercase letters that represent the station's name. For example, Stockholm commuter rail's Stockholm City Station has the station code Sci.[8] In Sweden the code is in a few cases a single capital letter, such as M for Malmö Central Station.
[11] Three-letter alpha codes (formerly called CRS codes - Computer Reservation System) are issued by National Rail which is responsible for railways in Great Britain. Station codes are not used by Northern Ireland Railways for stations in Northern Ireland.
In England, Scotland and Wales of the UK, railway stations are assigned three-letter codes and are issued by National Rail and are called the Computer Reservation System (CRS).[11]