The incident coincided with another Sleeper train breaking down in Cheshire, triggering a series of cancellations that lasted until last night.
It also came hard on the heels of week-long cancellations caused by a separate breakdown.
The faults over the last few days have affected both the Sleeper’s brand new £150 million fleet on the Edinburgh/Glasgow-London “Lowlander” route, and older trains on the London-Fort William service, one of three “Highlander” routes.
Passengers found themselves unable to get into the station in Edinburgh early on Saturday after being taken by coach from Fort William to join another Sleeper because the southbound service to London had been cancelled.
That was because the previous night’s London-Fort William Sleeper was heavily delayed because of a fault, not reaching the town until Friday afternoon, so staff were unable to get the required rest.
Passengers were eventually allowed into Waverley after being due to go to a nearby hotel for refreshments, but they did not board their train until around 1:15am.
Passenger Pauline Grice tweeted: “The complete c*ckup continues. Rays Coaches dropped us outside the Jurys Inn but didn’t tell anyone to go there, instead opened luggage boot and everyone headed to Waverley, who weren’t expecting us. No-one answering video call.
“Shocking!!!! @CalSleeper sort it out!!!”
Meantime, travellers on the southbound Edinburgh/Glasgow-London service the same night were forced to switch to other trains and coaches after it broke down at Acton Bridge, south of Warrington.
Caledonian Sleeper said it had been caused by a “door interlock fault”.
It also led to the cancellation of the London-Glasgow service on Sunday and the Glasgow-London service last night while repairs were made.
The latest disruption came a day after services were fully restored following one of the new trains on the London-Edinburgh-Glasgow route breaking down at Stafford in the West Midlands on 12 June.
Emergency brakes came on and damaged several sets of wheels.
John Whitehurst, transport managing director for Caledonian Sleeper operator Serco, said: “Our southbound Lowlander service, travelling from Edinburgh and Glasgow to London, terminated at Acton Bridge due to a door interlock fault.
“Following this, we arranged alternative travel to ensure guests reached their destination.
“Separately, the Fort William to London service was required to start from Edinburgh as a result of the delay to the northbound service on Friday morning.
“We apologise to all guests affected by these issues, who of course will receive full refunds.”
Caledonian Sleeper managing director Ryan Flaherty said today services would return to normal tonight.
He said: “We’re doing everything we can to reduce the likelihood of further disruption and hope to shortly take ownership of an additional unit which will allow us to take carriages in and out of service as required.”
The new trains are still due to be launched on the Highlander routes, including to Aberdeen and Inverness, on Sunday 7 July.
Other problems on the new fleet have included toilets and ensuite showers not working.