THE Rail Accident Investigation Branch has released a report into the cause of a major train derailment that closed the Settle-Carlisle line for seven weeks.

At 7.53pm on Wednesday, October 19 last year, five tank wagons in a freight train conveying cement powder from Clitheroe to Mossend, near Glasgow, derailed near Petteril Bridge Junction in Carlisle.

A number of wagons were damaged and there was significant damage to the track and bridge over the River Petteril.

This resulted in closure of the routes from Carlisle to Newcastle- upon- Tyne and to Settle for seven weeks, with trains into Skipton among those affected. No one was injured.

The derailment occurred because one set of wheels on the ninth wagon in the train stopped rotating during the journey.

These wheels had stopped rotating up to 55 miles (88 km) before the derailment and continued to slide along the railhead causing considerable damage to the wheel treads.

This meant the wheels were unable to safely negotiate a set of points just before Petteril Bridge Junction, damaging them and causing the ninth wagon to become derailed.

Five of the wagons derailed due to track damage and two fell off the side of the bridge where the railway crosses the River Petteril.

The ninth tank wagon was ruptured and landed upside down in the river, spilling a little of the cement powder.

The initial wheel slide was likely the result of a normal brake application made in low adhesion conditions. The wheel slide continued because the wheels could not restart rotation.

The non-rotating wheels were not identified by the signallers on the route, nor by the train driver or any engineered system, meaning the train was not stopped before it reached Petteril Bridge Junction.