British Transport Police were called to reports that a large group of teenagers were trespassing on the railway in Haslemere last Thursday.
The group of boys and girls reportedly gained access by climbing over fences at the Kings Road footbridge.
The police attended but the offenders had run off before they arrived.
Trespassing on the railway network is a major issue for Network Rail and the wider rail industry, and carries a risk of death, as well as a potential £1,000 fine.
There were 15 people who died in accidents while trespassing on the mainline in the year April 2021 to March 2022.
Trespassing includes picking up lost property from the tracks, crossing the tracks at any point other than at a level crossing, stepping off a level crossing onto an area where you shouldn’t be, and taking a walk down the side of the railway track.
If you step on the railway track, you face 25,000 volts of electricity, 400 tonnes of train, and the electrified third rail. But stepping foot on the land next to the track, or any area near the railway that isn’t open to the public, is also considered trespassing and is illegal.
A spokesman for Network Rail said: "People fail to understand the danger they put themselves, and others, in when they make the choice to stray onto the rail network unauthorised."