Whatever its fame and history, a locomotive can also be seen as a collection of skilfully designed, manufactured and maintained components.
Repainting might sound like one of the simpler stages of restoring a loco, but there are a lot of specialist skills involved.
Simon Kohler from Hornby writes about the effect the A4s have had on both his personal and professional life.
Mallard is such a popular locomotive that one prog rock band have even penned an ode to its magnificence.
Find out what’s been going on at Shildon with curator Anthony Coulls.