British Transport Police want to speak to a group of men after a fire extinguisher was let off on a train between Carnforth and Preston.
Fire extinguishers were also set off on the platform at Carnforth station.
Investigating officer PC Gez Cooper said: “A group of men who appeared to have been drinking, boarded the train at Preston, and generally made a nuisance of themselves to fellow passengers.
“During the journey, a fire extinguisher was set off, and a member of the public had to retrieve it from them.
“When the train arrived at Carnforth, another fire extinguisher was removed and let off on the platform.
“This kind of behaviour on a train is completely unacceptable.
“Safety equipment is there to be used in emergencies.
“Other passengers were clearly left annoyed by the antics of the group.
“Everyone has the right to travel without being made to feel uncomfortable.”
The incident occurred between 6.45pm and 7.15pm on Saturday, November 15,
Contact British Transport Police on 0800 40 50 40, or text 61016.