In accordance with an Indian Ministry of Railways decision, Indian Railways switched from its previous four-digit numbering system for passenger trains to a five-digit system on December 20, 2010.[1][2][3]
If the first digit is 5, 6 or 7, the second digit identifies the railway zone where the train is operated or maintained:
0 (E0XXX): Konkan Railway
1 (E1XXX): Some Central and West Central Railway zone trains
2 (E2XXX): Some Northern, North Central, North Western, North Eastern and East Central Railway zone trains
3 (E3XXX): All Eastern and some East Central Railway zone trains
4 (E4XXX): Some Northern, North Central and North Western Railway zone trains
5 (E5XXX): Northeast Frontier and some North Eastern Railway zone trains
6 (E6XXX): Some Southern and South Western Railway zone trains
7 (E7XXX): South Central and some South Western Railway zone trains
8 (E8XXX): South Eastern, South East Central and East Coast Railway zone trains
9 (E9XXX): Western and some West Central and North Western Railway zone trains
If the first digit is 8, the second digit is 2.[4] If the first digit is 9,
the second digit identifies the railway zone where the train is operated or maintained:
If the first digit is 0, 1 or 2 and the second digit is 2, the third digit identifies the railway zone where the train is maintained, except for 0 (Y20XX, the Shatabdi and Jan Shatabdi Express in all zones):
1 (Y21XX): Central and some West Central zone trains
2 (Y22XX): Some Northern, North Central, North Western and Southern zone trains
3 (Y23XX): Eastern and East Central zone trains
4 (Y24XX): Some Northern, North Central and North Western zone trains
5 (Y25XX): Northeast Frontier and North Eastern zone trains
6 (Y26XX): Some Southern and South Western zone trains
7 (Y27XX): South Central and some South Western zone trains
8 (Y28XX): South Eastern, South East Central and East Coast zone trains
9 (Y29XX): Western, some West Central and North Western zone trains
If the second digit is other than 2, the second and third digits identify the railway division where the train is operated and maintained.[6]
The fourth and fifth digits are random numbers, making each five-digit train number unique. However, on the Delhi Suburban Railway the fourth digit (4NXPX) indicates the following: