Railways led 3-0 at the interval with goals from Vandana Katariya (14th and 34th minute) and Roselin Dung Dung (16th). They added another two in the second session with Deep Grace and Ritu Rani finding the target in the 63rd and 65th minute respectively.
Vandana Katariya, who scored eight goals in the championship, was named player of the tournament.
"It is a wonderful moment for Railways as we succeeded in defending our title. We performed as a team and played every game as per the strategy planned by our coach. I think each member of our team played very well," Railways Skipper Jasjeet Kaur said after the final.
Earlier in the day, Jharkhand defeated Madhya Pradesh Hockey Academy 2-0 to finish third in the tournament.
After a goalless first half, Jharkhand dominated the proceedings as Lawerncia Kereketta struck in the 41st minute from a goalmouth scramble following a left-wing move.
In in the 45th minute, Binita Xess converted a penalty corner to give Jharkhand 2-0 lead.