Civil Engineering heritage: Scotland - Lowlands and Borders

The first Caledonian Railway Viaduct over the River Clyde was erected from May 1876 to October 1878. It had three main wrought-iron lattice spans, with slender diagonal web members, notable for having its rivets silently driven by hydraulic riveters invented by William Arrol.

As part of the early planning, a proposal was made in 1873 for a light twin-track, 11-span, wrought-iron plategirder bridge supported on cast-iron columns resting on a westerly extension of the piers of Telford’s Jamaica Street Bridge. The finely executed model for this proposal is now at the Institution of Civil Engineers’ museum at Heriot- Watt University. This proposal was abandoned in favour of the as-built design in 1875. An earlier proposal for a bridge at this site was in the 1840s to connect with the Edinburgh & Glasgow railway via a tunnel.

The 1878 viaduct’s central span was 186 ft. Its superstructure was demolished in 1966–67 except for its cylindrical piers now standing as sentinels to the operational viaduct (NS56SE 140.01). These remarkable piers, consisting of pairs of 15ft diameter cast-iron shafts, were sunk by open grabbing (see left in above view) to bedrock 85 ft below high water level ordinary spring tide. Its engineers, also for the 1873 proposal, were Blyth & Cunningham, and the contractor was Wm. Arrol & Co. The cost was £64400.

R Paxton and J Shipway 2007

Reproduced from 'Civil Engineering heritage: Scotland - Lowlands and Borders' with kind permission of Thomas Telford Publishers.