Children playing on Carlisle railway prompts warning
Children possibly as young as five have been spotted playing on a section of railway track where trains reach up to 90 mph (144 km/h).
British Transport Police said three children were spotted on CCTV on three occasions on the railway at Eden Viaduct in Carlisle.
Officers said the children were "dicing with death".
Sgt Garry Ashbridge said: "Train drivers cannot stop in time to avoid someone on the line."
He added: "The age of these children is astonishing - I fear one of them may even be around five years-old.
"I urge their older playmates or friends to lead by example and not encourage them to risk their lives by following them onto the railway."
Officers are urging parents to warn their children of the dangers of playing on railways.
A Network Rail spokesman said: "Not only is trespassing on the railway dangerous for the trespassers, it also puts the safety of others at risk."
"Additionally, trespass almost inevitably causes delays to rail services."