A PASSENGER train narrowly avoided being derailed after vandals put a pile of concrete slabs on a line.

And British Transport police warned today that anyone caught causing chaos on the tracks would be jailed.

Passengers on the 9.18pm First North Western train travelling from Colne had to be evacuated and taken by taxi to their Preston destination.

The train - an engine and two carriages - was travelling at around 50mph when it collided with a stack of concrete between Pleasington and Cherry Tree, Blackburn, on Sunday night.

Police chiefs say they are concerned by the "deliberate and dangerous" act which could have resulted in serious injuries.

They also fear an increase in incidents during the school Easter break.

PC Gareth Gray of British Transport Police said: "This could have been a potential disaster and the passengers were very lucky the train was not derailed on this occasion. Putting an obstruction on the tracks could have major consequences."

Sergeant Steve Murtagh of British Transport Police added: "There is no question that the obstruction had been placed in the middle of the tracks deliberately. The engine of the train was very badly damaged and had to be dragged away by another engine to be repaired.

"This is a very serious incident and we hope that anyone who saw or heard anything will come forward."

Two British Transport officers attended the scene and worked with railway staff for several hours to clear the site for later trains, which were delayed.

Spokesman for First North Western, Ric Gutteridge, said: "There were only four people on the train and they were all taken to their destinations by taxi within 30 minutes of the accident and the train was then cancelled. Later services were moderately delayed."

The concrete slabs had been taken from a nearby worksite.

Anyone with more information should contact British Transport Police on 0800 405040.