Shaft

The building is a ventilation shaft designed by James M Gale in 1887, located in the Loch Lomond and Trossachs National Park. It features a single-span, segmental-arched aqueduct bridge with a deep parapet wall that contains a conduit and large pyramidal-capped end piers. The structure is made of mass concrete faced with snecked, coursed Ben Cruachan granite. It includes a string course and a coped parapet, with tubular cast-iron railings adorned with ornamental flower motifs at the heads of the uprights. An early 20th-century concrete cover is also present.

At each end of the aqueduct, there are circular snecked, bull-faced granite enclosures that serve as ventilation shafts and access chambers. These enclosures have access gates and domed wrought-iron 'birdcage' tops with projecting copes. Additionally, there are stone steps, a retaining wall, and railings leading to the associated subterranean chambers. Security covers were added in 2007.