YOBS who put a concrete slab on a railway line could have killed train passengers, police said today.

The concrete, which covers cables at the side of the tracks, had been moved into the middle of the railway line about 200 yards on the Church and Oswaldtwistle side of Rishton railway station last night.

The slab caused extensive damage to the train's oil and air system but the driver and 30 passengers on the Blackpool South to Colne service escaped injury.

Cabling which had been pulled across the track was also severed.

The incident at 6.45pm caused a large amount of disruption to services in the area and is being investigated by British Transport Police.

Detective Constable Keith Holmes said: "These concrete slabs are extremely heavy for an adult to carry so this was a deliberate action.

"This obstruction could easily have derailed the train and caused serious injury possibly even death in circumstances like this."

A spokesman for Railtrack added: "At this time of year there are more and more of these incidents because children start playing on the tracks.

"Parents need to know where their children are and what they are doing. Quite apart from delays to trains playing on the tracks is extremely dangerous.

"The tracks are not a playground and although people might think it is clever to move things onto the track they are putting their own and other people's lives in danger."

Further damage to the train was caused by three youths who had been on board.

After being told the train was going to Rose Grove to await another vehicle, they smashed up the driver's cab causing further delays.

They then escaped after fleeing down the line.

Anyone with any information should contact PC Bill Rogers on 0161 228 5685 and quote log number 686, or Crimestoppers 0800 555111.