RAILWAY police have renewed an appeal for witnesses who may have seen young vandals placing concrete and a large boulder on an East Lancashire train line.

And officers warned that security will be stepped up to combat problems caused by children who play near railway lines.

Police were alerted to the Whitewell Road area of Accrington on Thursday March 21 when stones were hurled at the Blackpool North to York train. No damage was caused but officers who attended the scene at the rear of Accrington cemetery found a large boulder, concrete troughing and several ballast stones on the line.

The following day they were called back to the site after further reports of children throwing stones at trains.

Sergeant Paul Moores of British Transport Police said:

"Incidents like this can lead to a train being derailed and if another train is travelling in the opposite direction this can crash into the first one and lead to the loss of a large number of lives. Even just by being close to the track the children are risking their own lives.

Parents should be warning their children not to go onto the lines at all."

The stretch of line at the rear of Accrington Cemetery is historically one of the worst areas for incidents of this type, according to police, along with the section close to Grimshaw Street, also in Accrington.

And security is being stepped up.

Anti-vandal patrols have been put in place in Hyndburn, Blackburn and Burnley and plans to install police officers on trains for the summer are being drawn up.

Anyone found on railway lines faces a maximum fine of trespass £200. If caught placing items on the track and intent is proved, the person could face a life prison sentence.

Police have asked for witnesses to any problems -- including the incident on March 21 -- to call 0800 40 50 40 or 0161 228 5685. Alternatively they can contact their local police station.