The team must build a miniature train ferry at the Caledonian Canal, and cross a 12-metre span at Loch Lochy. It's not easy... And then the little train sets off on its epic journey across Scotland.
The team face huge challenges straight away as the build starts in Fort William
Silver Lady has a dramatic aquatic adventure, and the team have to build a huge viaduct
The train grinds to a halt on its first gentle hill, but one of the team has a brainwave
Dick upsets the train team by deciding to replace the steam train with an electric one
The train battles bad weather and the steepest part of the route. Will it reach Inverness?