Report 08/2021: Trains overspeeding between Laurencekirk and Portlethen
Overspeeding between Laurencekirk and Portlethen, Aberdeenshire, 4 December 2020.
Summary
On 4 December 2020, six trains exceeded a reduced speed limit which was temporarily in force between Laurencekirk and Portlethen, Aberdeenshire. A 40 mph (64 km/h) ‘blanket’ emergency speed restriction (BESR) had been imposed from the start of service on that day until 09:00 hrs, because of a forecast of heavy rain with the associated risk of an earthwork failure obstructing the line. In some instances, trains travelling through the BESR reached the normal maximum permitted speeds which varied along this length of line up to 100 mph (161 km/h) for the trains involved. In other instances, the reduced permitted speeds were exceeded for only parts of the BESR. The actual amount of rainfall was not sufficient to cause any earthwork failures, and no accident occurred.
The investigation found that some drivers were unaware of the BESR as they approached it, and others were unaware of its exact extent. A notice, displayed in the late notice cases at the locations where the drivers reported for duty, was the only information about the BESR provided to drivers. This notice did not convey information in a way that could be readily understood and remembered when drivers needed to apply it. Lineside signage is not used for BESRs and no other reminder was provided as trains approached the restriction. The BESR notice gave the limits in terms of both mileages and lineside features, but these did not correspond to each other. ScotRail had not recognised that use of the late notice case was an unreliable way to implement BESRs. However, some managers had improved reliability by local additions to the formal system. Although not directly relevant to the incident, RAIB observed that the BESR form contained in Network Rail procedures, and variants used in Scotland and on other routes, had shortcomings compared with good practice in human factors.
RAIB has concluded that the railway industry has more work to do to establish a suitable method for the imposition of speed restrictions, in response to extreme weather that has the potential to endanger infrastructure.
Recommendations
RAIB has made two recommendations and identified two learning points as a result of this investigation. The first recommendation seeks an improvement to the BESR notices provided to drivers and the second seeks a review of the methods used to implement blanket emergency speed restrictions. The learning points cover the importance of drivers being aware of information contained in late notices, and the need for safety critical communications to provide clear and unambiguous information.
Response to recommendations:
- RAIB will periodically update the status of recommendations as reported to us by the relevant safety authority or public body
- RAIB may add comment, particularly if we have concerns regarding these responses.