ScotRail has warned passengers in Fife that they should expect “significant” disruption to services this weekend.
Workers are taking part in strike action over the coming weeks as part of a row about overtime pay.
Trains between Fife, the north-east and Edinburgh will be cancelled on Sunday.
However, limited bus services will run to Queen Margaret Hospital in Dunfermline and Victoria Hospital in Kirkcaldy for key workers.
The RMT union, which is leading the strike, says it will proceed as planned if no agreement is reached with the operator.
General secretary Mick Cash said: "I have no doubt that our ScotRail members will show full support and stand shoulder to shoulder during the days of industrial action.
"We have made it clear that we will not allow ScotRail to divide the workforce and are demanding that ScotRail do what is fair and honour an enhanced rate for rest day working for all grades."
The operator has criticised the move, saying it will limit its ability to provide a service for key workers.
Graham Ralston, head of conductors at the operator, said: "The strike action will have no impact on ScotRail’s position on overtime pay increases, given the severe financial challenges we face.
"The strike is wrong during a global pandemic and will have a significant impact on those who need to make essential journeys.
"We will do everything we can to minimise the consequences of this action, but key workers will be adversely affected. Inevitable, many will have to find alternative and much less convenient ways to get to work to perform their life-saving duties."
ScotRail is encouraging passengers to check services before travelling.
The affected routes are:
· Aberdeen – Glasgow/Edinburgh
· Aberdeen – Inverurie/Inverness
· Aberdeen – Perth/Dundee
· Edinburgh – Inverness/Aberdeen
· Edinburgh – Inverkeithing/Glenrothes/Kirkcaldy/Perth/Dundee
· Edinburgh – Stirling/Dunblane
· Edinburgh – Tweedbank
· Edinburgh – North Berwick
· Edinburgh – Glasgow Central via Shotts
· Glasgow – Edinburgh via Falkirk High
· Glasgow – Anniesland
· Glasgow – Stirling/Alloa/Dunblane/Perth/Dundee
· Glasgow – Inverness/Aberdeen
· Glasgow – Cumbernauld
· Glasgow – Alloa
· Glasgow – Barrhead/Kilmarnock/Dumfries/Carlisle
· Glasgow – Stranraer
· Glasgow – Crainlarich/Oban/Fort William/Mallaig
· Inverness – Aberdeen/Edinburgh/Glasgow
· Inverness – Kyle of Lochalsh/Wick