[SystemSafety] Tram Accident in Croydon

[Peter Bernard Ladkin]

On 2016-11-17 10:36 , Mike Ellims wrote:
> 
> 1.       Driver says he blacked out, if so he was therefore was not operating the equipment. It is
> of course possible that he had an epileptic fit or similar i.e. just froze for a few seconds, I
> assume that it is possible for this to exist undiagnosed.

Yes. Also to remain traceless afterwards. I have two friends to whom this has happened when driving
cars, years ago. The one was on a freeway, felt strange and stopped on the hard shoulder as it
happened. The other rammed a tree (luckily from the middle of a slowish line of traffic; also
luckily, it was a late-model car with the best current crash-mitigation). Nothing untoward turned up
on thorough post-event CT scans in either case, and it has never happened to either person since.
They are described as "seizure-like events."

Not all momentary losses of consciousness are seizure-like events. Others can happen because of
interrupted blood flow to the brain, and so on.

Operator medical events are not at all unknown, in other words. Whether or not this was, it could
have been.

If these are ISO 9001 companies involved and if I were an investigator with a free hand, I'd go back
through the records to see where the issue of overspeed protection was raised and how it was decided
not to implement it. If I were the person who said "no", I'd be worried right now. And if the issue
had not been raised throughout design and implementation and I was a designer or implementer, I'd be
worried right now. I conclude that right now there are some worried people.

In terms of deaths, this is as bad as any since 2001, and in the last thirty years, there is only
Clapham Junction in 1988, Ladbroke Grove in 1999, and Great Heck in 2001 which are clearly worse.

PBL

Prof. Peter Bernard Ladkin, Bielefeld, Germany
MoreInCommon
Je suis Charlie
Tel+msg +49 (0)521 880 7319  www.rvs-bi.de





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