A Train guard was attacked after intervening in a domestic dispute on a journey from Leeds.
The 47-year-old was on the service to Huddersfield when he was headbutted and punched by a man who was arguing with his partner.
The attacker got off at Halifax and ran off.
PC Ruth Miller, of British Transport Police, said: “The member of rail staff assaulted was simply doing his job and attempting to assist a vulnerable passenger. Violent behaviour such as this is something we take very seriously, and we are pursuing a number of enquiries in relation to this case.”
The incident happened on the night of September 27. Witnesses should call BTP on 0800 405040.