Signals passed at danger (SPADs)

A signal passed at danger occurs when a train passes a stop signal without authority to do so.

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Further information about SPADS

While there are many SPADs each year, most of these 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 within the safety overlap provided at the signal.

The overlap is a clear section of track beyond the signal, usually 183 metres long, which provides protection against relatively minor overruns. Generally, trains have to run past the signal safety overlap before there is any potential of collision or derailment.

Can SPADS cause accidents?

SPADs are only one of the potential precursors to catastrophic accidents on the railway. Under 3% of all train collisions and derailments over the last 30 years have been directly caused by SPADs.  Since the introduction of the train protection and warning system (TPWS) serious SPAD incidents, and the risk arising from SPADs have been greatly reduced.

What are we doing about SPADs?

SPADs have always been of concern. We are continuing our efforts to reduce SPAD risk and numbers. There are many different ways of preventing SPADs or reducing their effects, including different types of train protection.

What is train protection?

This term covers equipment fitted to trains and on the track that either prevents trains passing signals at danger or reduces the consequences should they do so, by automatically applying a train’s brakes. While such systems do not prevent SPADs, they do reduce the risks posed by SPADs.

The train protection and warning system (TPWS) has been installed  across the network and is successfully reducing SPAD risk. There have been a number of incidents where TPWS has intervened to avoid a potential collision.
Information on the different types of protection available can be found in our train protection section.

More information on the different types of protection available can be found in our train protection section.

SPAD Risk Ranking

Since March 2001, the industry has been assessing SPADs using a SPAD Risk Ranking (SRR) tool which considers the actual and possible consequences of each incident. The SRR has 28 categories and SPADs ranked at over 20 are those with the highest risk of serious consequences while those between 16 and 19 give rise to concerns.

Those ranked from 1 to 15 carry little or no risk. Using the SRR as a measure, since 2001, SPAD risk on Network Rail’s infrastructure has reduced by approximately 85%. Further information is available on the Railway Safety and Standards Board website.

SPAD investigation reports

Following the Ladbroke Grove accident, HSE produced publicly available monthly SPAD reports, from October 1999 until September 2005. After that, Transport Ministers agreed that HSE should produce quarterly SPAD reports.

ORR have taken over responsibility for this, and will continue to publish quarterly reports. The Rail Safety and Standards Board (RSSB) still publishes monthly, publicly available, SPAD reports.

Last updated: 10 September 2008