An investigation has been launched into a runaway train on the Ffestiniog and Welsh Highland Railway line.

The Rail Accident Investigation Branch has launched a probe after a light diesel locomotive, pictured, passed over a number of level crossings and through Beddgelert station without authorisation, with the driver being unable to slow it down.

The locomotive had been travelling down a 1 in 40 gradient towards Beddgelert station on the Ffestiniog and Welsh Highland Railway at around 9.15am on Tuesday, 16 April, when it became apparent the operator was unable to slow down.

It was travelling at around 10mph (16km/h) for 1.25 miles (2km) without the driver being able to reduce its speed.

Investigators say: “It (the locomotive) passed over a number of open level crossings, through Beddgelert station, past a signal placed at danger and into a single line section without authorisation. The locomotive stopped when the gradient levelled out 0.6 miles (1 km) after the station. There were no injuries.”

The investigation will look into the factors that prevented the driver from stopping the locomotive, the maintenance of the locomotive and whether there are any underlying management factors.

A spokesperson for Ffestiniog and Welsh Highland Railways said that the railway would cooperate and be conducting its own investigation into the circumstances surrounding the incident.