25 August 2020
Initial information about the fatal landslide-induced train derailment at Carmont, Scotland
Late last week the Rail Accident Investigation Branch (RAIB) released an initial report about the train derailment at Carmont, south of Stonehaven in Scotland, which killed three people and injured a further six. Whilst this is only a provisional report, it provides considerable factual information about the accident. It confirms that the train struck the debris from what is described as a landslip onto the track. At the time of the accident (9:38 am) the train was travelling at 117.1 km/h. The impact with the debris derailed the train, which then travelled a further 70 metres before striking the parapet of the bridge. The image below, from the provisional report, shows the situation on the ground:-
The landslide that caused the derailment is just off the image. The RAB report provides some detail about the slope that failed:-
As the image above shows, to the left of the track (in the direction of travel of the train) there is a steep slope up to a field. Water draining from the field is captured by a drain running along the top of the cutting. The feeds a diagonal drain down to the trackside drain, consisting of a 450 millimetre (18 inch) diameter plastic pipe located in a trench backfilled with gravel. The excessive rainfall on the day of the accident appears to have overwhelmed the capacity of the diagonal drain, leading to overland flow that eroded the gravel, and some material from the sides of the trench, which was deposited on the track. It was this debris that derailed the train.
Clearly there is still considerable work to do to understand this accident. An interesting aspect will be the date in which this configuration of the drainage system was installed – a plastic pipe undoubtedly post-dates the construction of the railway, but it may bot be recent. The RAIB report will provide full detail in due course.
The UK is experiencing another spell of extremely heavy rainfall today, with yellow warnings of heavy rainfall across a swathe of the country. Further disruption to the railway is highly likely.
Quickslide 1: Floods and landslides in Turkey
Heavy rainfall in recent days has triggered flooding and landslides in the Turkish city of Giresun. At least eight people have been killed.
Quickslide 2: Boulder versus lorry…
The boulder won. Fortunately the driver escaped just in time.