A BRAKES failure on the Caledonian Sleeper could have led to “much worse” consequences if another train had been ahead of it, railway safety inspectors have found.

The Rail Accident Investigation Branch (RAIB) is investigating the incident on August 1, when the class-92 locomotive and eight new mark V carriages overran the platform at Edinburgh Waverley.

The RAIB said its preliminary investigation had found the driver “had no control of the brakes on the coaches” when he attempted to stop at Waverley on the overnight train’s morning arrival.

This was “because a brake pipe isolating valve was in the closed position when the train left Carstairs station,” where the train is split into Edinburgh and Glasgow portions after running as a single service from London.

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.

The train manager then activated an emergency device in one of the carriages to apply the train brakes, and the train came to a halt more than 700 yards beyond its intended stopping point.

Inspectors will now consider how the isolating valve came to be closed at Carstairs, along with how the train was driven, the suitability of procedures and the design of the brakes.

Rail union TSSA general secretary Manuel Cortes 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.”