Hundreds of trains were cancelled in the autumn after an overtime ban by the Rail, Maritime and Transport (RMT) union caused a major training backlog among staff learning how to operate two new fleets.
Training is still incomplete because only two thirds of the 96 new trains have been delivered to ScotRail, and the company was unable to say when it would be finished.
Disruption is continuing because of the training backlog, which has caused dozens of trains a day to run with fewer than the planned number of carriages.
Last year’s dispute was triggered by the train drivers’ union Aslef being paid more for “rest day” working than RMT members, such as other train staff.
It was settled in December, as The Scotsman revealed, when ScotRail offered the RMT more money.
However, the potential for further industrial unrest has been raised by Aslef being offered a new deal of an additional £75 for working on days off.
That would mean drivers being paid £375 – 25 per cent more than before – for such extra shifts.
Aslef Scotland secretary Kevin Lindsay said: “This should ensure a better delivery of service.
“I believe it’s a good settlement for Aslef members and the travelling public.”
But the RMT’s Scotland organiser, Mick Hogg, said: “We want the same, and if we don’t get an extension to our rest day agreement there will be industrial carnage – the choice is ScotRail’s.”
ScotRail said no agreement had yet been reached with Aslef.
It said the offer that had been made would have to go to the union’s executive committee first.
The train operator said it would begin rest day working agreement discussions with the other trade unions when their existing agreements reach their expiry date, which it said was the normal procedure.
ScotRail said it did not have a specific date for the training being completed.
It said that “short formations” – where trains run with fewer than the planned number of carriages – were largely because of training issues as a result of late delivery of the trains and last year’s now-resolved RMT dispute.
ScotRail has received around 40 of 70 new electric trains for Central Belt routes, which are being built by Japanese manufacturer Hitachi.
It also has received only about two of 26 refurbished diesel “High Speed Trains” for inter-city routes from refitter Wabtec.
Because of production delays, some of these trains have been pressed into service in an unrefurbished state, but this has required additional training because of their features, such as manually operated rather than electric doors.
The Scotsman revealed a breakthrough in the dispute in December when train drivers were offered an extra three hours’ pay for working on their days off. ScotRail is understood to have previously offered an extra two hours’ pay.
The letter, signed by ScotRail’s operations director, David Simpson, said it was the firm’s “best and final offer”. It was also signed by Mr Hogg and co-ordinator Jim Gray.
The agreement was to run until April, when it is expected to be incorporated in next year’s pay negotiations.
The RMT has said its members were paid between £112 and £140 for working on rest days, compared with £300 for drivers.
ScotRail has pledged to create an extra 140 “frontline” jobs to reduce the need for rest-day working and cover extra services being introduced over the next year.
Forty of these posts are to address “concerns of better work life balance and fatigue”.