Network Rail has announced that a section of the West Highland Line between Crianlarich and Fort William/Mallaig will be closed for nine days in March.
It will be shut to allow essential upgrade work to take place at Rannoch viaduct, just north of Rannoch station.
The work is part of a £1.6million investment to extend the operational lifespan of the structure.
Engineers will work around the clock from Saturday, March 16 to complete the project before the line reopens on Monday, March 25.
During the work, services between Glasgow Queen Street and Fort William/Mallaig will be impacted with buses replacing trains between Crianlarich and Fort William and between Fort William and Mallaig.
Meanwhile, buses will also replace trains from Tulloch, Roy Bridge & Spean Bridge stations to Fort William but there will be no services to Rannoch and Corrour during the closure.
However, the rail firm has said services between Glasgow Queen Street and Oban will operate as normal throughout the closure.
Zoe Monkhouse, Network Rail’s project manager for the Rannoch viaduct project, said: “The work we are undertaking in March is essential and cannot be delivered without closing the railway.
“We know that closing the railway at any time is never ideal, however, we always endeavour to plan our work for when fewer people are travelling on the railway and at a time which reduces overall inconvenience for the travelling public.
“We understand that this is not great news for those making plans to travel to visit family or friends or for leisure purposes, but our team will be working around the clock to deliver these works safely and on time.
“We thank passengers for their patience and understanding and apologise for any inconvenience this may cause.”
Phil Campbell, ScotRail Customer Operations Director, added: “We know the impact this line closure will have on customers, and we will be doing everything we can to keep people moving during the work.
“Replacement buses will be in operation, but journey times will take longer, and we encourage customers to check before they travel using the ScotRail website, app, or social media channels.”