A signal passed at danger – or SPAD – occurs when a train goes past a red signal without authority.
Most SPADs have little or no potential to cause harm because they are the result of minor misjudgements of distance or of braking capability, or they occur at low speed. In most cases, the trains stop well within the safety overlap provided, either by the train driver or through system intervention.
However, a SPAD still represents a glitch in the smooth running of the railway, causing disruption to operations, and in the worst-case scenario, the potential cause of a serious train accident.
SPADs have been the precursor to some of the most serious fatal train accidents in history, including more recently at Purley in 1989, Newton in 1991, Cowden in 1994, Watford in 1996, and at Southall in 1997.
The last multi-fatality train accident as the result of a SPAD occurred in October 1999 at Ladbroke Grove.
Over the past 15 years, SPAD risk has reduced by well over 90%. However, there is no room for complacency and industry continues to monitor and investigate SPADs to understand why they happen and what can be done to ensure the risk is managed.
A new strategy for reducing risk further
We have published the first phase of a new industry-agreed strategy to make the next step change in reducing and managing SPAD risk, and deliver safety and performance benefits to rail passengers and freight users.
The full strategy will be available shortly only to RSSB members
via Opsweb, but anyone can
download a short summary. You will need to familiarise yourself with this strategy if you are an infrastructure manager or railway undertaking, to ensure you can continue to apply best practice and contribute to better risk management.
Our work on SPADs
Over the last 15 years, we have helped our members get a much richer and more detailed understanding of the risk from SPADs, including better data. We produce a
monthly update on SPAD data.
We have also undertaken a great deal of
research to understand SPADs and consider ways of reducing the risk further.
Our human factors team has considered SPADs in the context of the working environment from a human-centred viewpoint, looking at the whole system and its influence on the way people behave and interact with the railway.
We also produce a range of operational safety learning resources for our members to use in their own companies to promote open and honest discussion about issues, including SPADs – this includes the
RED video series,
Right Track magazine and the business intelligence from
Learning from Operational Experience.
RSSB members have exclusive access to more information about SPADs via the
The key cross-industry groups which inform our work in this area are the
Train Accidents Risk Group (TARG) and
System Safety Risk Group (SSRG).