Trainspotting superstar Francis takes Chris to the world's biggest train show to recruit him to the epic restoration of a wrecked diesel engine.
The duo have 48 hours to strip their locomotive for painting: cutting out rot, welding fresh metal, removing every window, handle and sign.
Chris and Francis face huge setbacks with the wheels of their locomotive. The time and cost implications could be disastrous for the restoration.
Francis and Chris dig deep to help save their loco restoration when crisis hits. Will their high-risk strategy destroy their dream?
Chris and Francis try to make up lost time following lengthy wheel problems, but leaky brakes and a 12-tonne jigsaw stand in their way.
Chris and Francis install a 2.5 tonne traction motor, and head to the Highlands revealing 37025's past and a family connection for Francis.
The day finally arrives when Chris and Francis attempt to start 025's engine, but after two years of silence there's no guarantee it'll work.
Chris, Francis and the Bo'ness team race to assemble their beloved 37025 before her main line test. Any failure will scupper their Highland dreams.