The structure in the Scottish Highlands, made famous worldwide by the Harry Potter films, has undergone an extensive maintenance programme to safeguard its future for generations to come.

Network Rail, along with principal contractor AmcoGiffen, assessed the condition of the viaduct. Concrete repairs were carried out across the structure sympathetically, taking care to replicate its heritage appearance. New safety handrails for staff working at height were installed, along with renewing ballast retention systems at the ends of the structure. Ballast is the stone material under the track that maintains stability, drainage and prevents damage to the underlying structure.

Engineers also worked in the River Finnan, protecting the piers from erosion caused by the fast-flowing river. Meanwhile, specially trained rope access technicians descended from the viaduct, reaching and restoring areas that would otherwise be inaccessible.

Laura Craig, scheme project manager at Network Rail, said: “This project was years in planning due to the complexity of navigating such a large-scale, historic structure. Our highly skilled team faced numerous challenges, from preserving the viaduct’s original integrity to implementing modern engineering solutions. Every step of the process required meticulous attention to detail and a deep respect for its heritage.

“It’s an honour to look after the Glenfinnan Viaduct, knowing how much it’s loved all over the world. We’re proud to see it standing strong and it’s a testament to the dedication and hard work of everyone involved.”

The Glenfinnan viaduct opened in 1901 and is the largest mass concrete viaduct in Scotland, spanning more than 1,000 feet. The build cost £18,904 at the time, which is around £2m in today’s money.

Historic Environment Scotland have designated the structure as Category A, the highest level, meaning it’s of significant architectural and historical interest. As part of its preservation, Network Rail refrains from cleaning off efflorescence marks from the rain as it drains through, ensuring the character of the structure remains.

Ann MacSween, head of planning, consents and advice services at Historic Environment Scotland, said: “We welcome Network Rail’s investment into the careful repair of this iconic structure.

“Glenfinnan is the most impressive of several mass concrete railway viaducts and bridges along the West Highland Line, which was built 1897-1901. These bridges were mostly designed with an exposed concrete finish, rather than being faced in stone, and are the earliest railway bridges of this style in Scotland.

“Over a century after it was first built, Glenfinnan Viaduct still stands strong today, in no small part due to Network Rail’s excellent care.”

The restoration of the viaduct is part of a broader programme of work in the Glenfinnan area. A two-year, industry-leading pilot project is underway to enhance the natural habitat. The initiative includes planting trees across approximately 200 hectares to protect, restore and expand rainforest and peatland habitats. Additionally, deer fencing has been installed at Ardmolich to safeguard the newly planted native woodlands from overgrazing.

Network Rail is also investing £500,000 to renew over five kilometres of lineside fencing near the viaduct. The project aims to replace life-expired boundary fencing, ensuring the track remains safely separated from public areas.