A cyclist came within seconds of being struck by a train when she tried to dodge a closed level crossing barrier in Cambridgeshire.
The train driver was forced to apply the emergency brake when he saw the woman at Waterbeach on 12 September.
Richard Schofield, from Network Rail, said it was "one of the closest near misses we've seen".
British Transport Police are trying to trace the woman, who also ignored the flashing lights and warning signals.
More than 100 trains travel through the Waterbeach crossing each day, at speeds up to 75mph (120km/h).
Transport police officers have released images of the cyclist to highlight the dangers of misusing level crossings.
The footage shows her cycling up to the tracks before braking hard and scurrying backwards just as the train speeds past.
Moments later, she can be seen mopping her brow.
Jay Thompson, Greater Anglia's head of safety, said: "Not only was this incident very traumatic for the driver, but it could have resulted in the cyclist being killed."
Barbara Moss, who witnessed the near miss from the opposite platform, said: "What she did was unbelievable and I'd say she's very lucky to still be here.
"I've never seen anything like it, and I don't want to again."
Network Rail's latest safety campaign, Track Tests, revealed a third of people think they would hear a train in time to move out of the way.
However, route manager Mr Schofield, said: "The person using the crossing not only didn't hear the train, but ignored the warning lights and barriers, putting her life, the lives of passengers and the train driver in danger.
"Warning systems at level crossings are there for a reason, to protect users from the railway.
"I hope the release of this footage will highlight the importance of following the safety advice at level crossings."
A spokesman for British Transport Police (BTP), said: "Our main priority is to make sure the woman involved is alright, and find out exactly what happened.
"But this sort of thing is a criminal offence and people can be charged with failure to obey traffic signs or failure to stop."
Since 1 January, there have been 70 reported incidents at level crossings in Cambridgeshire, he said.
These include careless driving as well as people failing to stop or obey signs.
"Incidents of this nature, and this close at Waterbeach, however, are extremely rare," the spokesman added.