If there are changes in your route, make sure you always have enough time to walk from one platform to the other and never forget the possibility of delay that could make you miss the second train.
If you don't feel like spending many hours in a train, you can consider travelling by plane. Especially if you have the possibility to book in advance, flying to Kolkata can be definitely cheap.
Which stations serve the rail line Jaipur - Kolkata?
The trains to Kolkata leave Jaipur from Jaipur(JP) and arrive in Howrah Jn(HWH), Sealdah(SDAH) or Shalimar(SHM).
How long does it take from Jaipur to Kolkata and when do the trains leave?
The average duration of the journey is 28 hours and 30 minutes, but the fastest connections take you to Kolkata in 25 hours and 5 minutes. The first train leaves from Jaipur at 02:02, while the last one leaves at 14:02.