How to understand and manage overspeed risk
The Rail Accident and Investigation Branch (RAIB) conducted investigations at Sandy South Junction and between Laurencekirk and Portlethen. The risk of train overspeeding was noted in both, as was the need for industry to understand this issue better.
Overspeeding can occur in speed restricted areas. It can also occur in areas which are under a blanket speed restriction (BSR). Severe weather events are happening more often. This is also leading to speed restrictions being imposed more often.
The Train Accident Risk Group (TARG) is responsible for this issue. The Overspeed Group (OSG) a subgroup that reports to TARG. This issue is becoming more important, so TARG and OSG needed to better understand the risks of overspeeding.
RSSB held several workstreams to explore the risk of overspeeding. We used multiple activities to understand the risk from different angles.
We carried out interviews to find and assess national variations in the BSR process. These interviews included the criticality and resilience of different processes.
We assessed current processes and suggested some improvements. These were informed by several workshops we held with industry.
We improved the process and outputs of speed restriction design.
We defined the abilities and constraints of GSMR-acknowledged broadcasts. We did task and workload analysis about the use of GSMR and when it is best used.
As a result of this project, several issues about the risk of overspeeding have been improved.
These are:
- better understanding, as recommended in RAIB’s Laurencekirk and Portlethen and Sandy South reports
- better quality of data in the Safety Management Intelligence System for overspeed events
- regional data packs for operational risk reduction and mitigation have been produced
- use of GSM-R in some cases, as recommended in the report by Systra. TARG looks forward to future updates to this work.
The Overspeed Group is now recognised by ORR as an expert.