As a part of its successful bid, Serco had pledged to invest £100 million into the service, which was to be spent on, amongst other things, procuring new rolling stock.

Two services depart London Euston each night from Sunday to Friday and travel via the West Coast Main Line to Scotland.

[2] It became the first sleeping carriage used on British railways when it made a revenue earning trip on 24 February 1873 attached to a train at Glasgow for King's Cross via the East Coast Main Line.

During 1976, services from King's Cross ran to Edinburgh and Aberdeen, and from Euston to Glasgow Central, Perth, Inverness, Stranraer Harbour, and Fort William.

[10] On 5 March 1995, responsibility for operation of the Anglo-Scottish services was transferred within British Rail from InterCity West Coast to ScotRail.

[12][13][14] Eventually, British Rail agreed to retain the Fort William portion, albeit with a reduction four sleeping carriages to only one.

The arrangement continued until March 1998, at which point the freight operator English, Welsh and Scottish Railway (EWS) took on the contract.

[35] During May 2014, the franchise was awarded to Serco; at the time, the company pledged to invest £100 million in new trains that would include 'en suite' rooms and a new style of club car.

In late December 2015, staff called for a two-day strike because of health and safety concerns with the trains then in use and Serco's alleged failure to address them appropriately.

[38][39] In September 2019, another three-day strike was held after negotiations between the RMT and Serco broke down over claims of poor staffing levels and insufficient training.

[40][41] By mid-2020, the Caledonian Sleeper had considerably curtailed its services in response to the significant decline of passenger travel amid the COVID-19 pandemic.

[59] Similarly, going southbound, three separate services depart each of Aberdeen, Inverness and Fort William in the evening, hauled by a Class 73/9 locomotive up to Edinburgh.

The Aberdeen set consists of between two and four sleeper coaches (depending on demand) plus one seated carriage and one lounge car, all running throughout.

[64] Going northbound, the Lowland Sleeper departs London Euston at 23:50 (23:30 on Sundays), calling at Watford Junction to pick up passengers.

Similarly, in the southbound direction, two separate services depart both Glasgow Central (calling at Motherwell) and Edinburgh Waverley, and combine into one at Carstairs.

The train then calls at Carlisle, before running non-stop through to Watford Junction (served for alighting passengers only) and terminating at London Euston the next morning.

[69][70] However, due to mechanical problems, a Class 90 locomotive was used, initially hired from DB Cargo UK, but later changed to Freightliner.

[71][72][73] From 2015 until 2019, AC Locomotive Group heritage Class 86s and 87s were used to move empty carriages in London and Glasgow and occasionally operated the overnight passenger services.

When GB Railfreight started to provide the trains and crews for the Serco franchise in 2015, it was planned to use rebuilt Class 73/9s.

[77] Former train types operated by Caledonian Sleeper include: During April 2019, new Mark 5 carriages were introduced to service, however, the inaugural journey was more than three hours late arriving at London Euston.

One was addressed to the Rail Safety and Standards Board to change the wording of the railway rule book to make it clear that the brake continuity test should be undertaken after all coupling-related activities have been completed.

The second was addressed to Caledonian Sleeper to review the vulnerability of the isolating cocks on its rolling stock, to prevent inadvertent operation by persons or objects.