Vaishali Express - जितना सुंदर तुम्हारा नाम उतनी सुंदर तुम्हारी चाल - be my valentine - Rahul Vatsa

most probably 6-
one 4056 that leaves on 4th from delhi at 11pm
2nd 4055 that leaves on 4th from dibrugarh at 11pm
3rd 4056 that leaves on 5th from delhi,when the train of 4th is at farakka
4th...
more...

4055 that leaves on 5th from dbrg,when the train of 4th is at kishanganj
5th 4056 that leaves on 6th from dli,when the train of 4th is at mariani
6th 4055 that leaves on 6th from dbrg,when the train of 4th is at kanpur
thenext day both train reaches destination and same rake retruns...