Rope access technicians have taken to the skies, ascending and navigating the structure which sits 100ft above the River Finnan on the West Highland Line, 17 miles from Fort William.

This technique, known for its efficiency and minimal environmental impact, allows workers to reach and restore areas that would otherwise be inaccessible.

During this year-long project, which began in April, engineers are assessing the condition and strength of the viaduct before completing concrete repairs.

They’re also making improvements beneath the track to keep the stone ballast in place.

Alan Ross, director of engineering and asset management at Network Rail, said: “It’s not often, even in my job, that you have the chance to walk on the West Highland Line’s Glenfinnan viaduct.

“Given its importance and scale – we’re treating this refurbishment slightly differently, with rope access teams scaling the viaduct to assess and repair it.

“We’re doing it this way rather than using scaffolding as it’s more efficient and doesn’t spoil the view for the hundreds of thousands of people visiting this beautiful area.”

Back at ground level, engineers are working in the River Finnan, protecting the viaduct piers from erosion caused by the fast-flowing river. This protective work is even more crucial as the weather gets warmer and wetter due to climate change.

Alan added: “It’s been great to see the care and attention the team are taking on this job – we’re very proud to be custodians of this much-loved part of Scotland’s Railway and don’t take this responsibility lightly.

“There’s a lot more work still to be done in the coming months – we will continue to share updates of progress and you might even bump into some of our team at this year’s Glenfinnan Games!”

Glenfinnan Viaduct was completed in 1901 by Sir Robert McAlpine and was one of the last major constructions of the Victorian railway revolution.

It took around four years to build, spans 1000 feet and is the longest concrete viaduct in Scotland. It is Grade A listed meaning it is nationally important and Network Rail must refrain from cleaning off the marks from the rain that drains through it.

The total cost to build the viaduct was £18,904 – over £2m in today’s money.