School children from Birmingham are to stand near a track as a train speeds past at 125mph to persuade them not to play near railway lines.
Police say trespass on the tracks increases in the school holidays
Year six pupils from St Vincent's Primary school, Nechells, will stand at a blind corner on the Lichfield line.
Insp Stuart Middlemas, from the British Transport Police, said the aim was to raise children's awareness "just how fast a train is and how dangerous".
He said the pupils will be at a safe distance, wearing protective clothing.
Their gear will include high visibility jackets, hard hats and ear protectors.
Insp Middlemas said there were several "hot spots" along the rail tracks where people trespassed.
"There are incidents of trespass and particularly in the school holidays they do increase quite remarkably and a lot of the culprits are young children," he said.