The arrestee is Abdul Hasan.
Ahsan Habib, inspector of Rajshahi Railway Nirapotta Bahini (RNB), said three people were caught red-handed on Thursday noon from the station while they were stealing oil.
Later, a case was filed against seven people in this connection.
Besides, Abdul Hasan was suspended for his connection.
The three other arrestees are—Amjad Hossain, depot in-charge of Jamuna Oil Company, truck helper Elias Hossain and Mukul Ali, an employee of the company.
Police are trying to arrest three others accused—Ashfakul Islam, assistant manager of Jamuna Oil Company, buyer Rabiul Islam and truck driver Babu Ali Khan.
A probe committee led by Ashish Kumar Mandal, mechanical engineer (DME-loko) of Pakshi divisional railway, has been formed to investigate the incident.
The committee has been asked to submit its report within three working days.