Si and Dave return for the final stretch of their Restoration Road Trip and tonight they're heading off to work on a steam train by the name of the Night Owl. Fancy. The pair are really put to work this time around, as they help to forge a steel wheel taller than they are for Britain's biggest locomotive restoration. Dave takes a rather interesting trip down the cylinder of an old steam engine, to see how it's fared after 60 years of neglect. Wonder if he'll make it back out in time for the finale?