Hospitality bosses reliant on guests using the rail network say the first 24-hour train strike has already sparked a flood of cancellations.
Scott Meikle owns The Moor of Rannoch Restaurant and Rooms which sits next to Rannoch train station, 40 miles down a single-track road from Pitlochry.
He had 24 room bookings this week until news of the strike cut that to six.
More cancellations over the summer would be "devastating" for business, Mr Meikle said.
About 40,000 Network Rail staff have walked out in a dispute over pay, working conditions and redundancies.
'No viable alternative'
Mr Meikle told BBC Radio's Good Morning Scotland programme: "With the prospect of trains not being able to run, there is no viable alternative to get to us.
"The West Highland Line is a fantastic scenic route which goes through this vast wilderness of Rannoch Moor and we are right in the centre. So the railways play a huge part in getting our guests to us.
"The cancellations have already started and have been affecting us for the last few days. A lot of our guests are travelling and touring around Scotland and using the train lines is a vital part of their journey.
"That means guests who have been travelling for the last few days now find that they can't travel on - or home - from wherever they have been across Scotland."
Rail passengers have been warned to expect serious disruption as the first of three 24-hour rail strikes hits services in Scotland.
ScotRail has cancelled 90% of its services while cross-border services are also likely to be badly affected.
The result has serious financial implications for hotel owners such as Mr Meikle, who normally sees about 70% of his guests arrive and leave by train.
"As soon as there is disruption on the railways, it really does cause a huge problem," he said. "Not just for us, but business across the Highlands and across Scotland.
"We are constantly promoting sustainable and environmentally-friendly travel. But for communities like us, there is no real viable alternative. The railway is a vital part of the infrastructure.
"We open five days a week and we have five rooms, so for this block we had 24 [separate bookings] and at one point we went down to just six rooms. So huge levels of cancellations because guests cannot physically get to us."
The threat of continued disruption is a crippling blow to a sector still trying to recover from the effects of the pandemic.
Mr Meikle said: "Communities like ours, and hospitality in particular, were significantly hit by Covid and various lockdowns.
"There was very little we could during those periods - we can't do a home delivery service or home boxes, it's just not physically possible.
"So the sector across Highland Perthshire and the Highlands was really looking forward to a very busy summer with good bookings, but a lot of that has now been thrown into disarray."