The 400m long viaduct – which opened in 1876 and carries the Settle to Carlisle railway – is undergoing a £2.1M renovation programme including repairs to stone blockwork and drainage upgrades across its 24 arches.

As part of the work, laser and drone surveys have mapped in detail the Grade II listed structure and discovered a series of previously unidentified cracks to blockwork on the viaduct’s supports, which also need fixing.

When water gets inside these cracks and freezes in cold weather, it turns to ice and expands, making the damage worse, says Network Rail. Plans have been submitted to the Yorkshire Dales National Park Authority to carry out the extra repairs as soon as possible as part of the current restoration project.

“Being up close restoring Ribblehead viaduct for several months now, we have found deeper issues that need attention to protect this amazing feat of Victorian engineering for the future,” said Network Rail’s route asset manager for structures Marc Vipham.

“As with any heritage project of this kind, when plans need to change it is standard procedure to submit further planning applications to adapt our work. Carrying out these extra repairs now, when the specialists are in place and the scaffolding is already up, will save a huge amount of taxpayers’ money and stop us needing to come back all over again,” he added.

(Photograph: Tom Beresford)