Covid-related absences have caused Scotrail staff shortages and they have now been forced to cut back services during January.
The rail operator has had to alter its timetable between January 4 and 28.
Absences have already led to some trains being cancelled in the run-up to Christmas and these changes will mainly affect services which would normally run between Mondays and Friday in the central belt.
Services will be withdrawn or amended from 12 routes at various times in the day.
Passengers have been asked to check the status of their journey before they head to the station.
ScotRail operations director David Simpson said: "Like most businesses, ScotRail is not immune to the impact of coronavirus.
"We've been working flat out to run a safe and reliable railway in really difficult and rapidly changing circumstances.
"As we continue to battle against the impact of coronavirus, we want to provide customers with a level of certainty, which is why we are introducing some temporary changes to our timetable from Tuesday, January 4 until Friday, January 28 2022.
"We've looked to spread these changes out across the day where possible to minimise the impact on our customers, but people should plan ahead and continue to check the train times right up until they arrive at the station.
"We urge anyone travelling with us to stay safe and continue to follow government guidance.
"This includes maintaining good hand hygiene and wearing a face covering for your entire journey."
A Transport Scotland spokesman said: “We continue to work closely with rail industry colleagues to consider how best a predictable and robust service can be delivered while still providing the needed capacity during what continues to be a challenging period.
“We also agree with Transport Focus that these temporary changes are in the best interests of passengers.
“ScotRail is deploying a range of communications to ensure customers are kept up to date with the situation and is advising passengers to check their journey before they travel.”
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