RAIL bosses today offered a four-figure reward in the hunt for a firebug who brought chaos to Christmas train services.

Trains in and out of Kilmarnock station suffered eight days of major disruption after a vandal torched a vital signal box on the evening of Christmas Day.

Firefighters battled the blaze in the town's Bonnyton Industrial Estate for almost three hours and rail services were severely disrupted until January 3.

Engineers worked around the clock over the festive period to restore the rail link.

Now Network Rail is offering the "substantial" reward to help police catch the culprit.

David Simpson, route director of Network Rail, said: "This fire was a deliberate act of vandalism and we cannot let those responsible get away with it.

"We hope this reward will help the police get the information they need to catch and convict the people who brought misery to Kilmarnock travellers during the Christmas holidays.

"Despite the major damage to the signal centre we managed to get everything repaired in record time so that commuters returning to work could catch their normal train.

"Restoring services was a massive task and this was only possible because 50 members of Network Rail staff gave up their Christmas break to come in and help with the repair efforts."

The fire was reported at around 8pm on Christmas Day.

One witness spotted a man aged between 20 and 30, who was wearing dark clothing, near the scene of the blaze.

Call British Transport Police on 0800 40 50 40 with any information.