They discover several old railway tracks that run under the moors, some of them unused and also make friends with a boy named Jock, who lives at the farm with his mother and stepfather.

A watchman called Wooden Leg Sam tells them that "Spook trains" travel along those tracks, before chasing them away.

When Mr Andrews hears about the spook trains, he warns the children to stay away from the railway yard and tries to prevent Jock from meeting the Five over the next few days.

Julian and Dick secretly set off with Jock over the next two nights to watch for the spook train, leaving the girls behind.

[3] Five Go Off to Camp has also been adapted for a radio drama,[citation needed] while the gamebook The Haunted Railway Game (1983) was based on this novel.