The blaze caused partial damage to the coaches but no passenger was injured, East Central Railway PRO R K Singh said.
The four bogies -- two AC III tier, one AC II tier and one AC first class -- were set on fire by the students, who were agitated over being forced out by Railway Protection Force personnel as they had no tickets and were trying to occupy reserved seats, he said.
The group, comprising about 15 students, which had boarded the train at Ara, was spotted by the RPF personnel, who forced them out of the coaches during a halt at Bihta station, around 35 kms from Patna, Singh said.
The securitymen then bolted the doors of the bogies from inside following which the students got agitated and set the coaches on fire from outside, the PRO said.
The blaze was put out by fire tenders, he said.
Train services have been suspended on the Patna-Mughalsarai route, he added.