Retrotectacular: The Science of Derailing Trains


Look closely above and you’ll see there’s a section of track missing. There are actually two, a section from each side has been plucked out with a pair of eight-ounce plastic explosive charges — and yet the train keeps barreling onward. The World War II era reel is demonstrating some military testing of the effect of damaged tracks on a train. The amount of missing track the train can stand up to came as quite a surprise for us!

The test setup itself is neat. An old derelict locomotive is used. It, as well as a number of trailing cars, is pushed by a functioning engine from behind. Once up to about 26 MPH the pusher stops and the rest keep going. There are many tests, starting with just a few inches of track missing from one side. This gap is increased, then gaps are added both sides, then the two sides are offset. Even a 5-foot gap is crossed easily by the locomotive. The weak link turns out to be the empty cars. We suppose their mass is small enough that they can’t rely on inertia to keep them on the straight path.

If you don’t appreciate the destructive nature of this Retrotechtacular installment, you can still get your train fix. There is another offering which shows off the modernization of a signaling system.

[Thanks LC]

Retrotechtacular is a weekly column featuring hacks, technology, and kitsch from ages of yore. Help keep it fresh by sending in your ideas for future installments.

31 thoughts on “Retrotectacular: The Science of Derailing Trains

  1. Thats pretty impressive, I wonder how well modern trains fair under those circumstances(that’s only a theoretical question, I’m not expecting anyone to go and test it out for me).

    1. Probably should be tested, for anti-terrorism purposes. The results will never be released to the public, for anti-terrorism purposes.

      1. probably already been done. for anti-terrorism purposes. I probably saw it, but can’t talk about it. Same reason. Or, not.

      1. Not really. They reported that some guy said a six inch gap could lead to a derailment. Since the fractures that they showed are significantly oxidized, it shows that the high-speed train did go over those gaps many times before discovery.

        Of course it would not be surprising if a relatively tiny gap at the right place say, on a tight curve, would cause some heartbreak.

  2. The most impressive part of the video is, how such small amount of explosive cuts through massive steel like butter.

      1. The test is really about how much of a gap trains can traverse not about how to make it. How easy it is to make is secondary.

    1. Yes, especially if the ties are rotting. The spikes come out very easily with a prybar, and a lot of railroads only use one spike to hold the rails down now to save money (unless it’s a heavily used line.) You could dislodge a significant distance of rail very quickly with four people. Unless the line had regular inspection patrols (most don’t anymore,) it’d go undetected easily.

      1. There are special vehicles that run on the rails and check them as they go. I think they still have to use them.

  3. A literal failure of linear thinking; dislodging the rails laterally or spreading them even a small amount (beyond the wheel flange widths) will cause immediate derailment.

    1. The point is to do it in-out with plastic explosives, because you don’t have too much time to stand around a track you just sabotaged and you don’t have a ten man crew of engineers to move the tracks around.

      The quickest minimum effort is to blow a gap in the tracks, but for that you need to know how big a gap you need for effect.

      1. You could perhaps knock up a device to combine both. Some piston-like thing, where a small explosion blows 2 rods outwards. The rods each rest on the inside of a rail. So set it off, and it pushes the rails outward just as described.

        Just an idea… but they do use explosives in more subtle manners than just blowing stuff to shit, nowadays, in all sorts of industrial uses. There’s tools already powered by explosives.

        1. Sabotage teams would have to carry that piston around though and it’s wouldn’t really be something you could easily hide either unlike explosives.

          1. Dunno, couple of crowbars for the piston rod, or just lengths of scaffold. A brick at the end for the piston head. 2 of these, bricks on the inside, next to the bomb, to absorb the blast and turn it into pushing motion. Doesn’t have to be efficient or safe. Railway steel is pretty soft as I understand, quite pliant. You can cut a lot of corners when you just want to destroy stuff, rather than build it, and you don’t care about safety or reuse.

            Using something like this guerilla weapon I realise I’ve just invented, would probably do more damage to rails than just a simple unconfined blast.

          2. Just to re-follow myself up, my second invention of this thread… a version of Mythbusters combined with Scrapheap (or Scrapheap Challenge as I think they sold it to the Yanks as)…

            Teams of enthusiastic engineering-types have to destroy water towers, sabotage tanks, etc, as ingeniously as possible. In a fictional resistance-movement type thing, in a goodie country occupied by baddies. Okay, it’d probably never get funded. Maybe in Iran or somewhere.

    1. Try privatising the fuckers. Worked on many industries over here in the UK. Of course they still get massive government subsidies, by “privatise” they meant the capitalist free-for-all money fountain type, not the one where the new owners have to actually bear most of the costs.

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