Dick Strawbridge and a team of model train enthusiasts try to build the world's longest model railway. They face huge challenges as soon as they start in Fort William.

The model train leaves Fort William heading towards Inverness, but the tiny train ferry crossing doesn't go well, and the team also have to build a huge viaduct.

The tiny train grinds to a halt on its first hill, but one of the team has a brainwave. The build team decide to construct an ambitious curving bridge across a stream.

The teams face a series of tricky challenges on one key day. And Dick upsets the train team by deciding to replace the tiny steam train with an electric one.

It's the last stage of the tiny train's epic journey. She's in bad shape and still has to face bad weather, rocky terrain and the steepest part of the route.