A senior Railway Police official said 30 revolvers were found inside the bag, lying under the seat during routine checking at the ladies' compartment by RPF personnel.
No arrest could be made as yet.
The Railway police suspect that the consignment was being taken to Namkhana in South 24 Parganas district from where the revolvers would be supplied to anti-socials.
The firearms were suspected to have been made at illegal gun making units at Munger in Bihar.