Starting 20th December 2010, the train numbers for the trains running under the Indian Railways has been changed from a four digit format (eg 1234) to a five digit format (eg 12345).
Following are the methods to find the new train numbers for the same:
Scenario 1: You know the old 4 digit train number:
1) Go to the official Indian Railways link.
2) Next, click on either of the two locations on the home page (shown in the next two screenshots).
3) Enter the old train number. ( For example, I use the train name “Mumbai Rajdhani” which had its old train train number as 2951.)
4) And click “Get New Train Number”.
5) The new train number is displayed (in this example, the new train number is 12951).
Scenario 2: You do not know the old 4 digit train number:
1) Go to the official Indian Railways link.
2) Click the option “Train Running Information”.
3) Enter any part of the train’s name and click “Search”.
4) A drop down menu is generated with the various trains, the names of which contain the string of text searched for.
5) The new 5 digit train number is listed along with the train name.