The village of Titfield is linked to Mallingford town by a single track railway which is closed down because it is losing money. The villagers, roused by train enthusiast Weech, plan to run the line independently with rich, drunken eccentric Valentine providing the money. But their action arouses the opposition of the local bus company run by Pearce and Vernon Crump, who attempt various acts of sabotage when the new line is opened.