Vandalism is a "threat" to the rail network

Although the driver did not need medical attention, he suffered severe facial bruising and left his cab at nearby Mossend shortly after the incident.

EWS safety manager Fiona Crozier said: "EWS urges all parents to make their children aware of the dangers of these acts of vandalism.

"If these attacks do not cease, then tragically the vandal or the driver will be killed."

Other incidents have occurred at Carfin, Shotts and Whifflet, also in Lanarkshire.

A motorcycle was left in the path of trains in Morningside, Edinburgh, in January, and a wheelchair was placed on the line at Niddrie the following month.

Railways inspector Gerald Kerr said in December that vandalism was the biggest problem facing the rail industry in Scotland.

Mr Kerr said there were 139 train incidents in Scotland between April 1999 and April 2000 - the majority caused by vandals.

Rail safety has been in the spotlight following crashes at Selby and Hatfield in England.