Nearly 50 people have been killed after taking shortcuts and trespassing across railway lines in the last year, according to Network Rail, with the majority of these being men.

To highlight the problem it has teamed up with 400m hurdles champion Dai Greene to warn young males about the dangers of taking a short cut across the tracks.

Out of the 49 accidental deaths on railway lines between April 1 last year and March 31, 88% were male with more than a third aged between 16 and 25.

Greene appears in an online video as part of a campaign called Track Tests which is being launched today.

In it he is shown struggling to run along tracks due to rain, grease on the line and other hazards, which aims to show that if a fit, agile athlete is unable to get out of the way of a train, then others will not have a chance.

Track Tests will also feature a Facebook page and mobile and online advertising campaign over the next four weeks.

Welshman Greene, who won gold at the World Championships last summer, said: ''Day in day out, I train hard to make sure I am as quick as I can be.

''On the running track it's important that my reactions are lightning fast but on the train track - during filming - that didn't count for much.

''The experience has brought to life just how many dangers there are on the rail tracks - most of which I knew nothing about. I hope that this film really helps Network Rail to show people that taking the risk is never worth it.''