SCOTLAND’S troubled a Caledonian Sleeper train trains are set to face further disruption after guards and stewards overwhelmingly voted to strike.

Rail union RMT said members had voted by a margin of 10 to one to down tools on a turnout of over 80 per cent.

The union has now upped the pressure on outsourcing giant Serco, which operates the service, by calling for the route to be renationalised.

The dispute is over stress and mental health issues resulting from increased workload and the chaotic roll-out of the new fleet.

If the union’s executive opts to call workers out in September the action could cripple the roll-out of the company’s flagship new trains on the Highlander routes from London to Aberdeen, Inverness and Fort William.

RMT general secretary Mick Cash said: “Our members on the Caledonian Sleeper are sick and tired of paying the personal price for the botched introduction of the new fleet and that is why they have delivered this overwhelming vote for action.”

New Mark 5 carriages were due to begin service last year but they were only introduced on Lowlander services to Edinburgh and Glasgow at the end of April.

Their launch on the Highlander service was then postponed to July 7 before it was announced they would instead be introduced “later in the year.”

Since entering service the new carriages have been beset with problems, with passengers decanted into hotels and replacement buses on several occasions.

Mr Cash said: “It is time for Serco to wake up and take note of the appalling working conditions their mismanagement has lumped on their staff and to take action to resolve this dispute.

“We are calling on the UK and Scottish governments to nationalise the sleeper, and consign Serco’s chaotic handling of this iconic service to the dustbin of history.”

Caledonian Sleeper managing director Ryan Flaherty said: “We’re deeply disappointed by the result of the ballot. I believe we have shown a real commitment to dealing with the issues the RMT has raised and indeed there was an acceptance on all sides that progress was being made.

“We remain open and willing to engage in further talks to avoid industrial action and are fully committed to delivering the best possible service to guests.”

The union said it was “available for genuine and meaningful talks.”