YOBS brought the rail line between Blackburn and Preston standstill by dangling lumps of wood in front of speeding trains.

A group of teenagers smashed up a wooden bridge in Speedwell Street, Mill Hill, yesterday afternoon and used rope to drop pieces of timber at windscreen height in front of horrified drivers.

Network Rail chiefs closed the line completely for an hour and half severley disrupting services across Lancashire.

The line was re-opened at 4pm, but with a 5mph ‘walking pace’ restriction close to Mill Hill station.

A total of 11 trains were delayed, and three services were cancelled altogether.

The first incident was reported to the authorities at 2.24pm by the driver of the 12.13 York to Blackpool westbound service.

One object struck the roof of the front carriage and the driver stopped the train to examine the damage.

A Network Rail spokesman said there could have been fatal consequences.

He said: “Unfortunately from time to time kids do this sort of thing.

“Dangling things from a bridge can only be malicious.

"There is the intention to break the windscreen of the train and possibly injure, if not kill, the train driver.

"This is a very serious offence.”

The 13.44 Blackpool South to Colne train, travelling in the opposite direction was then targeted, but the driver stopped short of the bridge after seeing the objects dangling at windscreen height in time.

The spokesman said: “British Transport Police were advised and we sent structural engineers to assess the bridge itself to see what was done and if it was safe.

“The damage was to a footbridge. The vandals had taken apart the wooden panels from the fixed metal structure.”

The incident caused considerable delays for hundreds of passengers using the line, including services between Blackpool and Colne.

British Transport Police confirmed they were working with Network Rail at the scene.

Last month, “stupid” teenagers put bricks, bottles and other debris on the railway line at Cherry Tree station to “see what would happen”, British Transport Police said.

Several trains had smashed through the debris before a concerned member of the public spotted what was happening and contacted officers.