This is a single track and single bore tunnel of 450 ft on the east side of Loch Treig which passes under the west slope of Creagan Faraidh. It is close to, and to the south of, the closed Fersit Halt. It is built on a deviation from the original route, which was just to the west and at a lower level.
The tunnel was created in 1929 when Loch Treig became a reservoir for the Lochaber Smelter and its level was raised. The Loch Treig Dam is 2/3 of a mile to the north. A portion of the trackbed had to be raised above the new high water level of the loch. The disused section of the line is usually covered by water. At low water the portion alongside the tunnel is well preserved: a stone shelf cut out of a hillside. The original route did not require a tunnel.
Also known as Fersit Tunnel.
Fort William [1st]
| Loch Treig Signal Box|
Loch Treig Base Camp
Loch Treig Valve Shafts
Loch Treig Speeder Shed
Loch Treig Dam
Fersit Speeder Shed
Fersit Fitting Shop
Fersit Cement Shed
Stob Coire Sgriodain
|Location names in dark blue are on the same original line.|
A Base Camp
During the construction of the West Highland Railway one of the ^base camps^ was at the north end of Loch Treig, a location close to where the later Loch Treig Dam and Loch Treig Tunnel were built.
From this camp supplies were ferried by small flat bottomed ^puffer^ to the lochside locations where work proceeded. The line, going south, was slowly climbing to the summit at Corrour Summit, locations further south needing aerial ropeways to reach the works area from the lochside - by the south end of the loch the line was 450 ft above the water level.
|07/08/1932||West Highland Railway|
Loch Treig Tunnel and diversion opened. The line was re-aligned at a higher level as the Loch became a reservoir, part of the Lochaber Aluminium Works scheme.