CALEDONIAN Sleeper executives issued a safety alert to the rail industry after a brake problem caused one of its trains to make an emergency stop when it overshot the platform at Edinburgh Waverley station.

The Rail Accident Investigation Branch raised their concerns over brake failure while launching an investigation into how the Lowland Sleeper sparked an emergency at Edinburgh Waverley station.

The RAIB said the train eventually came to a halt, but over 700 yards beyond its intended stopping point.

While there was no damage or any injuries as a result of the incident the RAIB said the outcome could "potentially have been worse, had it led to a collision with another train".

READ MORE: Brake issues to Caledonian Sleeper caused emergency at Edinburgh Waverley

Investigators say that on the approach to Edinburgh at 7.26am on August 1, the driver discovered that the train's braking performance was "well below normal" and it "failed to stop as scheduled".

An RAIB preliminary investigation indicated that he had no control of the brakes on the coaches because a brake pipe isolating valve was in the closed position when the train left Carstairs station.

The RAIB said this meant that the only effective brakes on the train as it approached Edinburgh were those on the locomotive, which were "insufficient to maintain control of the train".

Now it has emerged the Sleeper train operator Serco issued a safety alert to the industry in relation to the incident, four days later.

The RAIB said the reminded railway staff of the importance of "carrying out a brake continuity test after all other train preparation activities".

Neither the RAIB, Serco or the Rail Safety and Standards Board would allow sight of the alert.

READ MORE: Investigation underway after Caledonian Sleeper 'overshot platform' at Edinburgh Waverley

The train was eventually brought to a stand still by the operation of an emergency device in one of the coaches by the train manager, which caused the train brakes to apply.

The incident meant services to London, Dunbar, North Berwick and Tweedbank were cancelled or delayed, before the train was pushed back to the platform.

The Caledonian Sleeper has suffered a number of setbacks since it relaunched with a new £150m fleet in April. On its first night, both north and southbound trains rolled into Glasgow and Euston hours behind schedule.

Manuel Cortes, general secretary of The Transport Salaried Staffs' Association union called for speedy action over the incident.

He said:  “Only good luck and the quick thinking of the train manager saved the passengers on the morning of August 1. We cannot rely on luck to keep passengers safe. 

“The failure of the brakes could have led to a catastrophic accident. We need to find out as soon as possible what led to the brake valve not being opened and then act to put in place whatever is needed for this not to happen again.”