Aluminium works were established at Dolgarrog in 1908, served by cheap hydro-electricity generated using water from the reservoir above the village. But getting people and materials to the works proved difficult as the Llandudno Junction to Blaenau Ffestiniog railway was aligned on the other side of the River Conwy. Various short-term solutions were found including a steam wagon, electric car, river vessels, 2-foot gauge tramway and a canal. All were short-lived.

But in 1916 the works’ owners, the Aluminium Corporation, completed a standard gauge spur of about a mile in length, forming a junction with the Conwy Valley line about three-quarters of a mile to the east. Interchange sidings and a loop were provided there, as well as a small platform which allowed the labourers to travel free to work by train, having transferred to the company’s two carriages waiting in the loop.

The line’s principal structure was an impressive crossing of the River Conwy. A pair of 85-foot trusses support the deck across the main channel whilst the side spans use 120-foot cross-braced trusses. The various members join beneath riveted steel plates. Both the abutments and piers are formed of concrete.

The passenger service was withdrawn in the early 1932 but goods traffic continued, peaking during the war before declining through the Fifties. The line closed in 1960 and the track was lifted four years later.

Today the structure’s timber deck carries two water mains and a footpath.