Newtork Rail have released video of young boys running across the railways a bid to keep passengers on the platform and off the tracks.
The video shows a group of youngsters at Mill Hill station in North London running from a train onto a platform and then across two railway lines onto another platform.
One youth drops his bag on the track and returns to retrieve it. The group was never caught.
More top news
MCM London Comic Con runs from May 24-26.
An emotional Lewis Hamilton put his Mercedes on pole for the Monaco Grand Prix and said: "This is for you, Niki."
Teenagers, aged 13 and 14, were taken to hospital on Friday morning but passed away, South Yorkshire Police said.