A FREIGHT train which derailed in Ayrshire causing extensive damage to the track and major disruption to train services for more than two weeks was travelling at nearly six times the speed limit when it crashed, a report has found.

The freight train, loaded with sand and ballast, was travelling at 28mph when struck another stationary freight train during Network Rail engineering works at Logan, near New Cumnock.

The force of the collision on August 1 last year knocked 18 wagons and a locomotive off the track and closed the line to passenger services until August 17.

No one was hurt but the driver was left "badly shaken".

The freight train should not have been going any faster than 5mph in a work site, but a report by the Rail Accident Investigation Branch (RAIB) found that the driver may have mistaken the speed limit for 40mph and that due to a misunderstanding during a telephone briefing with the lead engineer he also believed the stationary freight train was a mile further up the track.

Investigators also warned that there was a danger of routine speeding in work sites because of a "general lack of monitoring" which encourages freight train drivers to exceed the 5mph limit because they "are aware that there are unlikely to be any consequences of violating the rule".

Investigators analysing on-board data recorders, or "black boxes", from freight trains using the site also found that there had been a number of other speed breaches in the run-up to the crash.

The RAIB report found that it was 11.11am when the driver, then travelling at 33mph, first applied the emergency brake after catching sight of the stationary freight train ahead. It was at a distance of 168 metres (184 yards).

However, investigators estimated that the combination of the train's speed and the downhill gradient meant it would have taken at least 375 metres (410 yards) for the moving freight train to come to a halt.

The report adds that "shortly after" applying the emergency brake, "the driver got out the driver’s seat and braced himself behind the seat on the right-hand side of the cab as he realised a collision was unavoidable."

The freight train slowed only slightly, to 28mph, and the locomotive containing the driver's cab was one of the vehicles thrown from the track.

Investigators who interviewed the driver said that he was aware of the rules about driving in work sites and "explained that the default maximum speed in a work site was 5mph".

However, the driver claimed that he believed he was travelling in a "possession" zone at the time - a section of line that is closed to railway traffic to allow engineering work to take place on the infrastructure, but which is not classed as a work site.The speed limit for possessions in 40mph.

Investigators found that a warning sign at New Cumnock marking entry to the work site would not have been visible to the driver "as it was lying face down between the rails" when he passed.

The report added: "The RAIB’s review of the evidence concluded that it is possible that the driver might have mistakenly believed he was travelling in a possession."

However, investigators stressed that this did not explain why the driver was travelling at more than 30mph on a curved section of track where the train's "needed to be reduced by about half" to comply with safety rules.

The lead engineer told investigators that he had briefed the driver to travel at 5mph, but the driver said he did not recall being given this instruction.

The driver also misunderstood the location of the stationary freight train, believing it was a mile further along the track that it actually was.