The victim, a 30-year-old local man, was returning to the cycle rack at the station where he had secured his bike when he saw a man riding away on it.
He gave chase and managed to grab the man who then assaulted him with the bike lock before attempting to flee.
A member of the public chased the man and pulled him off the bike. The man ran off towards Sheffield bus station on foot allowing the victim to retrieve his bike.
The incident took place on October 30 around 6pm but British Transport Police (BTP) officers only yesterday appealed for information.
Detective Constable Bob Hunt the investigating officer, said: “The victim and member of the public showed great courage and managed to foil this attempted theft. Despite being hit by the metal bike lock luckily the victim didn’t sustain any serious injuries.”
British Transport Police can be contacted on 0800 40 50 40. In calls, please quote background log B5/ NEA of 29/11/2012.