Rafiqul Islam, stationmaster of Ullapara Railway Station, said six bogies and the locomotive of the train derailed near Ullapara railway station around 2:30pm.
Later, three of those caught fire immediately, he said.
Visiting the spot in the afternoon, Sirajganj Deputy Commissioner Dr Faruk Ahamed said a five-member probe body has been formed with additional deputy commissioner Firoz Mahmud as its head. It was asked to submit a report within five working days.
The other members of the committee are officials concerned of upazila administration, police and fire service, said Ullapara station master Rafiqul Islam.
General Manager of west zone of Bangladesh Raiway Ahsan Ullah and other high officials visited the accident spot.
Ahsanullah said technical glitch might be the cause behind the accident and another probe body will be formed by Bangladesh Railway.
A relief train reached the spot and started rescue operation, he added.
Monjil Haque, deputy managing director of Sirajganj Fire Service, said six units of the fire service doused the fire of the train after frantic efforts.
Earlier on Tuesday, at least 16 passengers were killed and over 100 others injured in a collision of two trains at Mandbagh in Brahmanbaria.
The deadly collision between Dhaka-bound Turnanishita from Chattogram and Chattogram-bound Udayan Express from Sylhet took place around 3 am.