A £2.1m restoration project on one of Yorkshire’s most recognisable landmarks looks set to be extended after engineers warned works had revealed large stone blocks could shear off and fall on people.
Network Rail has applied to the Yorkshire Dales National Park Authority to alter its revamp of the grade II listed Ribblehead Viaduct, which had been due to be completed next month.
The railway infrastructure operator was granted permission last year to carry out the first major repairs, including re-pointing eroded mortar joints and replace broken stones on all 24 arches which span to the 104ft-high structure, since the 1990s.
The work was seen as crucial to maintain the Settle to Carlisle railway route and “star attraction” which draws crowds of visitors to the area.
Phil James, north-west route director for Network Rail, said: “We know the structure is incredibly important both locally and internationally, and we want to give it the care and attention that it deserves so it can be enjoyed by future generations.”
To maintain the integrity of the feat of Victorian engineering, the original construction of which saw more than 100 workers die, the revamp is subject to strict rules, such as a precisely defined mix of mortar can only be applied to the structure using hand tools.
Fresh documents submitted to the park authority state following the erection of a huge scaffold system on the viaduct a close inspection of the structure identified numerous vertically cracked stone blocks.
They said unless action was taken to repair they could fall from height above the route of the Yorkshire Three Peaks.
The papers state: “The approach to stitch the cracked blocks seeks to prevent further deterioration of the fabric and subsequent loss and allows for original historic masonry to be retained in situ conserving both the special architectural and historic interests of the viaduct.
“The additional interventions are consistent with the sympathetic ongoing maintenance of the structure and the scale of intervention required is the minimum necessary to conserve the viaduct whilst ensuring the safe running of the Settle and Carlisle line, an active railway line and the safety of the public visiting the structure.
“As with the consented stitch repairs, the additional stitch repairs are specified in order to prevent the large-cracked masonry blocks of Pier 12 from shearing and falling onto the public below.”