Rail workers have confirmed three days of strike action following complaints of “intolerable” stress on the Caledonian Sleeper.
Staff in rail union RMT have been told not to book on for any shifts for 72 hours from midday on Sunday.
It comes after concerns were raised regarding poor staffing levels and workers receiving insufficient training.
Fresh talks were held on Monday with a view to finding a resolution to the dispute and postponing the action, if not cancelling it altogether.
But RMT has said Caledonian Sleeper operator Serco are “quite happy to leave their staff hanging out to dry” – claiming it “blocked progress” during the meeting.
In addition to the strike action, union members have been instructed not to work any overtime or rest days.
And from midnight on Wednesday, October 2, they have been told to avoid higher-grade duties and only work to their original job description.
The union’s general secretary, Mick Cash, said: “Promises made to us to address the serious concerns of the Caledonian Sleeper staff have not been honoured.
“The failure of Serco to come up with any serious progress in key talks yesterday leaves us with no choice but to go ahead with our industrial action exactly as planned.”
He added: “RMT members have been put under intolerable personal stress as a result of the company’s mismanagement of the sleeper service.
“They know it, they have promised to do something about it but they have failed to deliver.
“The move to strike action is entirely Serco’s fault and the public will understand that.”
Picket line protests have been arranged to take place in the evening on Sunday and Monday outside the train stations in Aberdeen, Inverness and Fort William.
Demonstrations will also be held in Glasgow, Edinburgh and London.
Ryan Flaherty, Serco’s managing director of the Caledonian Sleeper, said: “We are deeply disappointed and frustrated at this industrial action by the RMT, but most of all we are bemused as they have been unable to explain what will bring this dispute to a resolution.
“We have met the RMT and Company Council on many occasions and the changes they have requested have either been completed or are underway, including the recruitment of more staff at Edinburgh, Glasgow and London for a six month period whilst the new Mark 5 carriages settle in.
“We recognise that the problems we had introducing the Lowland Sleeper were challenging for everyone involved and we are very grateful to all our staff for their efforts and the way they rose to meet the challenge, but we are pleased that in the past weeks the situation has been steadily improving.
“This action is completely unnecessary and we urge the RMT to come back and tell us what they want. We are ready to go to mediation and hold further discussions.”