A fleet of new supertrains operating in the Bradford district has come under attack from youngsters throwing rocks.

About six of the Class 333 trains have been bombarded with stones since they were introduced in January.

Yesterday, a window was shattered on the Skipton to Leeds service at 3.48pm.

Passengers also reported an object thrown through an open window on an old-style train travelling between Bradford Forster Square and Skipton at 5.30pm. No-one was injured.

A spokesman for train operator Arriva Trains Northern today said that the supertrain had been taken out of service, but added that the double skinned window, which helps to protect passengers, had not been smashed by the rocks.

He said: "We now have 14 of the trains in service every day. Obviously, this does cause a lot of expense and down time as we have to take the trains out of service to repair them.

"But the main concern is safety. The last thing we want is somebody sitting on the train being hit by a rock through the window."

The attacks were mainly out of school hours, he added.

A British Transport Police spokesman said today that officers had yet to receive reports of yesterday's attack.

He added: "We would encourage passengers to report these incidents - it's very dangerous to life and limb. If people do not report them, we cannot deal with them."

The Class 333 trains were introduced at the end of January, replacing Class 308 units on the Airedale and Wharfedale lines which link Leeds, Bradford, Ilkley and Skipton.

One has already been pulled out of service after being covered with graffiti while stationary at Skipton station.

Anybody who witnesses an incident can call the British Transport Police on 0800 405040.