ScotRail boss Alex Hynes promises improvements
The boss of the ScotRail Alliance has promised improvements to services after a surge in cancellations.
Alex Hynes said problems in training staff to operate new trains were the main reason for recent delays.
Hundreds of services have been cancelled or had fewer coaches, leading to overcrowding, since the introduction of a new timetable.
Mr Hynes apologised but said travellers should notice "significant" improvements next week.
The new timetable, introduced on 9 December, promised the "best railway Scotland has ever had" with 100 new services and faster trains.
Refurbished Intercity 125s are coming into service, along with brand new Hitachi class 385 electric trains.
But Mr Hynes, managing director of ScotRail Alliance - a partnership between Abellio ScotRail and Network Rail - said delays in the delivery of the new trains had "compressed" the time available for training.
He also said an overtime ban by members of the RMT union had hindered preparations, although that dispute has now been resolved.
He told BBC Scotland's Newsdrive programme: "We are expecting to deliver improvements day by day and week by week.
"We are expecting significant improvement next week. As we sit here today our teams are working 24/7 to reduce the number of cancellations down to as low as they possibly can so we can restore services."
However, he conceded that travellers would face a "difficult" few days while training on new trains and routes put pressure on staffing.
Some of the cancellations on Monday were due to an early morning signalling fault at Perth, but the majority of problems were linked to staff shortages.
The RMT said the operator did not have enough staff to run a full service and carry out training at the same time.
Scotland organiser Mick Hogg said: "If staff refuse to work the overtime, the employer ScotRail has a problem.
"No-one can be forced to work their free time, their rest days. ScotRail is very much reliant on staff working the overtime."
ScotRail has urged passengers to check service information and to claim under its Delay Repay Guarantee if they are delayed by more than 30 minutes due to a cancellation.
Last week ScotRail released new figures showing that punctuality had improved, and was at its best since September.
The train service, run by Dutch firm Abellio, said 83.4% of trains met the rail industry performance standard of arriving less than five minutes behind schedule. The yearly average now stands at 87.3%.
However, these latest figures do not reflect the most recent cancellations.