The extension opened on 1st April 1901 and contains a series of major viaducts, including the iconic Glenfinnan Viaduct
Construction began in 1897 under the engineering partnership of Simpson & Wilson, with Robert McAlpine and Sons appointed as principal contractor. The project would go on to cement the company’s reputation for innovation, particularly through its pioneering use of mass concrete on an unprecedented scale.
Among the most notable structures delivered were a series of major viaducts, including the iconic Glenfinnan Viaduct (pictured right, under construction in 1898), alongside those at Loch nan Uamh, Morar, and Borrodale.
At the time of its completion in 1901, Glenfinnan was the longest concrete railway bridge in the UK, showcasing the firm’s willingness to push engineering boundaries.
The project was not without its challenges. Early sections progressed relatively smoothly, but the route’s geology, comprising mica schist, quartz, and gneiss proved difficult to excavate. The use of gelignite for blasting accelerated progress but was dangerous. In response, inspired by a trip to the dentist, Malcolm McAlpine introduced innovative drilling techniques, including water-powered turbines drawing from nearby lochs. (The dentist had used high pressure water to power the drill.)
In response to resistance from local landowners over the appearance of concrete, McAlpine added red colour to the mix and, by scoring the surface, emulated the look of dressed granite. This blend of engineering innovation and sensitivity to context remains a hallmark of the company’s legacy.
A special ceremony is taking place today (Wednesday 1st April) at Glenfinnan Museum to mark the occasion.
A military engineering project of unprecedented size and complexity, we played a significant role in the construction of two artificial port facilities to support the allied forces following the D-Day landings in Normandy.
Familiar to Harry Potter fans the world over, the Glenfinnan Viaduct has been wowing visitors since construction was completed in 1901. Part of a wider West Highland Railway extension, the innovative use of concrete at this scale was an industry first and featured in The American Engineering News in 1899.
The acknowledged home of football for more than three quarters of a century, the construction of Wembley Stadium and the British Empire Exhibition showcased Britain as world leaders in concrete construction.
Highway Inspector, Andy Walker, has been recognised with a prestigious national award for inspiring the next generation of engineers.
During Net Zero Week, Adam Robinson, Senior Sustainability Manager at Sir Robert McAlpine, explains why data-driven decision-making is fundamental to achieving the construction industry's sustainability ambitions.
During Net Zero Week, Company Carbon Manager, Simon Leek, outlines how our Sustainable Engineering Excellence strategy is strengthening our ambition to become Net Zero by 2045
