The incident took place on 4 May at a crossing near Eridge in East Sussex, with security cameras showing two girls foolishly hanging about on the railway tracks - on which trains regularly travel at speeds of 85mph.
This wasn't an isolated incident, either. In nearby Bewbush, close to Ifield, three boys were photographed walking along the tracks just 10 days later.
It comes amid a spike in youth trespassing on railway tracks since lockdown measures were first introduced.
Network Rail has released the images in a bid to spread awareness about the dangers of putting yourself on the path of a train.
Nicola Dooris, community safety manager on the south east route, said: "Unfortunately during lockdown, we have seen an increase in the numbers of young people messing about on the railway.
"On that section of track trains often travel at 85 mph and at that speed, unlike cars, trains can take hundreds of metres to stop, a fact many young people don't realise.
"Using CCTV like this I'm often able to track down young people and talk to them.
"I'd much rather do that than help our staff cope with the aftermath of young people being killed."
Vincent van der Hoeven - Network Rail's head of route quality, health, safety and environment - added: "We really must get the message across to children and their parents the dangers of trespassing on the track.
"We are putting efforts into getting the message across in schools and on social media through our 'Parallel Lines' film and 'You vs Train' campaign."
In March, police echoed these warnings, appealing to parents to ensure their children understand the dangers of trespassing on railway tracks.
Superintendent Alison Evans of British Transport Police said: "We often warn families at this time of year as the evenings get lighter and children prepare to enjoy school holidays.
"However, this year our concerns are more acute, especially as we are not able to get into schools ourselves to pass this message onto children directly.
"Trespassing on the railway can have serious, life-changing consequences for the individual, their loved ones and the wider community.
"Please, make sure you know the rail safety basics and pass that knowledge onto your loved ones.
"Lead by example and stay off the tracks."
Chosen for YouChosen for You
Most Read StoriesMost Read