The Glenfinnan Viaduct, made famous by the ‘Harry Potter’ movies, is an engineering marvel.

But at 123 years old, it’s desperately in need of restoration work.

‘Rope access teams’ have been working day and night to strengthen the bridge’s concrete arches.

Every year, hundreds of visitors gather at the viaduct each day to watch the “Hogwarts Express” train cross its 21 arches.

Watch.