Cairngorm funicular railway
Viaduct appraisal report by COWI UK Limited, December 2018
Specialist engineering consultancy COWI was appointed to carry out a detailed investigation of the viaduct infrastructure supporting the Cairngorm funicular railway in September 2018.
COWI’s appointment followed an earlier inspection by ADAC Structures that had identified safety concerns and led to the funicular service first being reduced, then withdrawn.
The viaduct supports 1.65km of the 1.9km railway track, while the remaining 250m at the top of the line lies within a tunnel.
COWI appraised the substructure and superstructure of the viaduct, which is made predominantly of concrete and supported by 93 piers, placed around 18m apart.
COWI’s first report was finalised and delivered to HIE in December 2018. It identified numerous failings in different parts of the viaduct including foundations, piers and beams. It also concluded that bearings appeared to be overloaded, with some that were significantly displaced and sliding beyond their limits.
The 2018 report was subsequently peer-reviewed in line with best practice. COWI also carried out more detailed investigations during 2019 and worked on design solutions that will enable the funicular to be brought safely back into service.
Reports arising from these further investigations are currently being reviewed for publication by Highlands and Islands Enterprise, and will be released shortly.