CALEDONIAN Sleeper has issued an apology after passengers were hit by major disruption to ten services affecting its new fleet of trains between Scotland and England.

The issues which saw trains running up to three hours later, and saw passengers switching to daytime trains, comes after it emerged that complaints about the Sleeper have rocketed by 67 per cent after the introduction of the troubled £150m new fleet.

Services from Euston to Aberdeen, Fort William and Inverness stopped near Arbroath on Monday morning due to a train engine failure - meaning passengers had to transfer to a new daytime service. They were understood to have been running up to three hours late.

Meanwhile passengers on the London-bound Highlander from Aberdeen, Fort William and Inverness were forced to do the same due to suspected overhead line issues at Preston. Passengers on the northbound Lowlander heading to Glasgow and Edinburgh also had to switch trains due to the power problems.

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An investigation has been launched by Caledonian Sleeper and Network Rail to find out what happened at Preston.

A Caledonian Sleeper spokeswoman said: "That caused major issues on how to get guests up to Glasgow and Edinburgh. That has been resolved."

Meanwhile the Euston to Inverness and Fort William services were running up train problems causing delays of up to an hour.

Magnus Conn, operations director for Caledonian Sleeper, which is run by Serco said: “We would like to apologise to guests who were travelling on last night’s services who were involved in the delays that took place across our Highlander and Lowlander routes.

"The two delays at Preston are suspected to have been caused by issues with overhead line power which we’re working with Network Rail to investigate.

"We are working hard to ensure that all guests reach their destination as soon as possible.”

The Herald: Caledonian Sleeper train

A Caledonian Sleeper spokeswoman said that it is believed the issues had been resolved to allow tonight's services to run smoothly.

It comes as it emerged the overnight services run by Serco between Scotland and London attracted the highest complaint rate of any train operator according to the the Office of Rail and Road (ORR) regulator.

There were 206 complaints per 100,000 journeys between April and June, up from 123 in the same period last year.

It was revealed a fortnight ago that Serco had completed the introduction of its new fleet of overnight trains on all routes between London and Scotland.

They were debuted on the Lowlander route between London and Glasgow/Edinburgh in April.

It was confirmed that all services including the Highlander routes between London and Aberdeen, Inverness and Fort William are now being operated using CAF Mk V coaches.

The trains feature new comfort seats, as well as rooms with double beds and en-suites.

READ MORE: Further delay to Caledonian Sleeper service sparks outcry

Various forms of accommodation are available on the trains, including Classic Rooms, Club Rooms, Caledonian Double and Accessible Rooms.

It also includes redesigned comfort seats with a personal locker, reading light and charging point with Wi-Fi services across the train.

"Our new trains have been years in the making and to see them complete their introduction to service is extremely exciting for everyone involved," said managing director Ryan Flaherty earlier this month. "We have worked really hard to learn lessons from introduction of the trains on the Lowlander route earlier this year. We are now confident that all passengers can rely on the Caledonian Sleeper to provide the journey of a night time."