ScotRail has admitted breaking a pledge that its busiest rush-hour trains will not miss station stops.
The train operator confirmed some such services have cut out stops.
ScotRail was unable to provide figures yesterday, but claimed the number was “miniscule”.
It comes a month after The Scotsman revealed ScotRail had ended “stop skipping” by its most heavily-used trains in the morning and evening peaks following passenger anger.
ScotRail stressed that missing out stops was not designed to get trains to their destinations on time.
Managing director Phil Verster said it was purely to reduce knock-on delays to other trains using the same routes by avoiding them also being held up behind a late-running service.
A spokeswoman for the ScotRail Alliance, which also includes Network Rail, said: “As announced in November, our new approach means we protect the busiest peak-time services.
“The majority of these are commuter trains travelling towards a major population hub in the morning, and away from it in the afternoon.
“An exception is peak services between Edinburgh and Glasgow via Falkirk High, where we protect services in both directions at the height of the morning and afternoon peaks.
“This happens rarely. We are talking about a miniscule number of services, but we do appreciate it has an impact on customers on board, hence the new approach which will mean far fewer customers are affected if we have no other option but to miss out a station.”