Two trains are going to crash. What do you do?

One of the Twitter testing community, @JariLaakso, posted this question:

Two trains are going to crash. Brakes don’t work. What would you do?

Of course, you can’t answer this without asking a lot of questions to establish context.

  • Are you on board one of the trains? If so, are you a passenger or a member of the train crew? If train crew, are you in the driving cab, or elsewhere on the train?
  • Is your train actually moving, or is it stationary and about to be hit by the other train?
  • If you’re not on board the train, are you a bystander, or someone like a signaller?
  • How long before the collision? Just seconds, or longer than that?
  • Is there anyone on board the trains at all? Perhaps it’s a staged crash for a film?
  • Is the “crash” even an impending collision? Or is it a case of software gone blue-screen-of-death meaning the brakes can’t be released and the train needs rebooting before it can go anywhere? This may sound silly, but I’ve been on a Virgin Trains Pendolino that had to do precisely that.

The actual answer turned out to be none of those things, but that’s not really the point. It’s about asking the right questions to get the information you need to be able to answer the original question “What do you do?”.

As an aside, real-life rail (or air) accident reports can often be worthwhile reading for a tester. I’m not talking about sensationalist reports of death and destruction, but the technical stories behind the accidents and how they occurred.

I remember reading L.T.C.Rolt’s classic “Red For Danger” at a formative age. It’s a very well-written and readable account of the evolution of railway safety throughout the steam age. It starts with the development of early primitive signalling systems from the 1840s onwards, and tells of the lessons learned from each successive serious accident. As the story moves into the 20th century, increasingly sophisticated systems from signal interlocking to better and stronger rolling stock meant far fewer disastrous accidents. But even the best systems can fail, with sometimes fatal consequences, and the book explains how.

It’s essentially the story of bugs.

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6 Responses to Two trains are going to crash. What do you do?

  1. Serdar says:

    I’m interested in the stories behind air accidents for the same reason – there’s almost always a story there about the failure of a whole series of interlocking systems in some tiny, unprecedented way.

  2. Tim Hall says:

    And the lessons learned from those unprecedented failures are the reason rail and air are so safe compared with other means of travel.

  3. PaulE says:

    It can be frustrating, though, when the procedures default to the safest system of all – not to run any trains.

    Probably the most dangerous thinking is to assume the system is perfect. The unsinkable ship isn’t.

  4. Tim Hall says:

    That’s a valid point. In past times when a signal failed they’d do “stop-and-proceed” working with trains running through the affected area at walking pace, which meant there were delays, but thinks kept moving. Nowadays everything is at a complete standstill until the problem is fixed.

  5. John P says:

    I don’t know about rail, but I understand that air accident investigators have pretty draconian powers at their disposal. IIRC, they can enter/search/seize without a warrant, demand assistance from anyone, talk to anyone they like. Of course, they have to justify the use of these powers within the context of the investigation otherwise they are deep in it. Just thought I’d chuck that bit of trivia in.

    Actually, here’s an interesting link from Google. A memo between the chief fire officers and the AAIB which gives a bit more detail.

  6. Rob says:

    I salute another “Red For Danger” fan! That book probably accounts by itself for my interest in railways: certainly I got interested in signalling from it, and began hanging around local (Stockport) signal boxes. (And discovered that one of our local relief signalmen had helped to clear up the wreckage of the Harrow & Wealdstone collision as a National Serviceman.)

    There was a terrific play in the Edinburgh Festival Fringe a few years back entitled Charlie Victor Romeo, which was taken from Cockpit Voice Recorder transcripts of air accidents.