The Rail Accident Investigation Branch is looking into how two trains went through an emergency speed restriction between Laurencekirk and Portlethen, Aberdeenshire, on 4 December 2020 without reducing speed.
The incidents happened between about 06:35 and 07:40 on 4 December 2020. Two passenger trains passed through an emergency speed restriction located between Laurencekirk and Portlethen stations, at speeds of up to 100mph (160km/h), significantly exceeding the temporary maximum permitted speed of 40mph (64km/h).
The first train was travelling north from Dundee to Inverness, the second was travelling south from Inverness to Edinburgh. The emergency restriction had been introduced as a precaution in case forecast heavy rainfall caused ground movements affecting the safety of the railway.
Neither of the train drivers was aware of the emergency speed restriction at the time they drove their trains over the affected section of track. The events were identified after a Network Rail signaller noticed the relatively short time taken for the second train to pass through the area. The first overspeed was then identified using electronic records of train movements. There were no injuries or damage as a result of these incidents.
RAIB’s preliminary examination found no evidence that any other trains which used the line on 4 December did not observe the speed restriction. However, until the second overspeed was identified by the signaller, the only notification to drivers was a printed notice at their booking on points. Lineside signage was not provided by Network Rail processes applicable to this type of speed restriction. After the second overspeed, the method of working was changed so trains were stopped shortly before reaching the restricted area while signallers reminded drivers about the reduced maximum permitted speed.
The investigation will determine the sequence of events that led to the incidents and include consideration of:
- The processes for advising train drivers of emergency speed restrictions;
- Any overlap with issues identified during the on-going RAIB investigation of the fatal accident on 12 August 2020 at Carmont, a location within the area covered by this emergency speed restriction (although there was no emergency speed restriction at Carmont on the 12 August);
- Any relevant underlying factors.