Station codes

The names of train and bus stations are often abbreviated by codes that are only a few characters in length. The station codes are intended to be unique within a given country, and knowing them can be useful for booking.

Although in many cases you can get by with knowing only the station name, it's nonetheless useful to know the code of the station you are travelling to. Common reasons include:

• Some large cities are served by more than one station – either in the city itself or a suburbs. Kolkata, for instance, is served by five major stations: Howrah (HWH), Sealdah (SDAH), Kolkata (KOAA), Santragachi (SRC) and Shalimar (SHM).
• Some cities have identical names; Portland (Oregon) (PDX) was named for Portland (Maine) (POR) but is on the opposite coast. The code is a useful confirmation that you have a ticket to the correct town, and that you are going to the correct Waterloo station.

Using the codes can make entering destinations on transportation websites quicker.

Some stations are known by their code and referenced by local public transport with them, and thus the codes can be useful when communicating with taxi drivers. They may also appear in diverse contexts as a colloquial nickname for the city which the station serves.

National rail carriers (such as Amtrak) have been known to assign their own non-standard codes to train stations on their own lines.

In some cases, a single station has different codes for different lines; Mumbai's Dadar Station, for instance, uses DR for the Central Line  Central  and DDR for the Western Line  Western , and the Seoul railway station uses 133 for Line 1 services, 426 for Line 4 services, P313 and 0001 for Korail services (commuter and intercity, respectively), A01 for AREX services and X106 for GTX-A services. In other cases, a single station has different codes for different services; London St Pancras International, for instance, uses STP for domestic and SPX for international services.

The Indian Railways (IR) uses station codes whose length varies from one to four letters. Stations with one-letter code include Gondia (G), Jalna (J), Raipur (R), Srirangapatna (S) and Yeliyur (Y).

Station codes are commonly used not only in booking but also in the short names of railway lines and services. For example, the Howrah–New Jalpaiguri line is often called the "NJP line" after the New Jalpaiguri station, and one can find various Visakhapatnam-bound trains named "VSKP Foobar Exp".

While IR station codes rarely change, often preserving the stations' former names (like MAS for Chennai Central, formerly Madras Central), they do occasionally change more than once. For example, the station code of Mumbai's Chhatrapati Shivaji Maharaj Terminus was changed from VT to CSTM in 1996 when it was renamed from "Victoria Terminus" to "Chhatrapati Shivaji Terminus". It was changed again to CSMT in 2018 after adding "Maharaj" to the station's name.

South Korea's Korail, as well as metro systems in cities like Seoul, use purely numeric station codes. Since the Korean language uses Hangul, most station codes are all-numeric. For example, Korail's Seoul station has 0001 as a station code for ticketing, while Aheyon has a station code of 242.

Although the International Air Transport Association generally assigns three-letter airport codes, they also assign three-letter codes for non-aviation facilities, including train stations, bus stations and ferry terminals. Such stations are generally used in rail air alliances or code-sharing arrangements between airlines and public transport operators. By assigning stations an IATA code, passengers on trips involving those stations can be ticketed all the way through the journey, including being checked straight through to their final destination, without the bother of having to claim their baggage and check-in again when changing between the surface and air portions of a trip. At other places, passengers have to carry their baggage onto the train, but need no separate train booking process.

Other identifiers include:

• World Meteorological Organization (WMO) identifiers, typically five-digit numeric values, uniquely identify weather stations.
• UN/LOCODE, the United Nations Code for Trade and Transport Locations, assigns five-letter codes to trade and transport locations such as seaports, rail and road terminals, airports, Postal Exchange Office and border crossing points. The first two letters are the country code, so "US NYC" is New York City.

• Airport codes
• Station articles