"Our initial investigation has revealed that a passenger was carrying some inflammable material but it is yet not clear how the fire broke out," said the official.
The blaze was doused by the motorman and fellow travellers, he said.
The incident took place between 7.30 pm to 8 pm in CST bound train originating from Khopoli.
"After the motorman was alerted about the fire by the passengers he stopped the train and used his extinguisher to douse the flames," said A K Jain, senior spokesperson of Central Railway.
Jain said the incident did not affect the operation of local services.
"Motorman's statement has been recorded and charges will be slapped against the commuter who was travelling in train with inflammatory belongings," said the official.