Signal failure – Two Dreaded Words We Don’t Want to Hear

On 12 December 1988, during the morning rush hour, three commuter trains carrying an estimated 1,300 passengers collided in Clapham, Europe’s busiest railway junction.

Hundreds of people were injured in the crash and 35 people lost their lives. It remains one of the worst incidents in London’s Fire Brigade’s history.

What happened 

As reported by London Fire brigade a crowded commuter train hit the rear of another train, which was standing stationary just south of Clapham Junction station. The impact on the stationary carriages shunted it to the right, where it struck a third oncoming train. The wreckage of the trains was so entangled that at first it wasn’t clear how many trains were involved. First reports were of two trains, but it soon became clear there were actually three.

The cause of the crash
According to assent risk management the cause of the accident was said to be incorrect functioning of the signalling system. It had not registered the stationary train. Two weeks before the crash, the automatic signal WF 138 had been installed as part of a large-scale re-signalling operation. This involved disconnecting old wiring and reconnecting new wiring. However, it was found that the old wiring had been disconnected only at one end and pushed aside with no insulating tape applied. This action was found to have tragic consequences. This allowed the old wire to move back to its former position and give a false feed of current.

An independent inquiry was later held by Anthony Hidden, QC for the Department for Transport. The inquiry led to several recommendations around signalling and staffing whilst also identifying that one of the signalling technicians had only had 1 day off in 13 weeks of work.

Lord Tordoff said “One has a strong feeling for the old saying that for want of a nail the shoe was lost, for want of a shoe the horse was lost, and so on. A chain of accidents occurred here. However, from what I have read, the report deals not only with the technical aspects of the accident which led up to the disaster but of the culture that lies behind it and the failures of individual people and management.”

Digital railway technology may have moved on since 1988, and we may have learned from the past tragedies. However, human error, system failure and poor maintenance will always lurk in the background. At SigTech Rail we never rest on our laurels and we are 100% committed to putting safety first and foremost in all that we do!