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View Diary: UPDATE: "Driverless" Crude Oil Train Explodes, Destroys Canadian Town (257 comments)

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  •  My observation of couplers was that they had a (4+ / 0-)

    secondary retainer available that could be set manually for loads such as this.but that requires hiring someone to engage them.

    •  Air brakes would apply automaticly... (6+ / 0-)

      If the cars accidentially uncoupled. The air brakes on trains work by releasing when air pressure is present, and as the cars came uncoupled the air hoses would be disconnected, the air pressure would leak out, and the brakes would automaticly be applied...

      Unless someone closed the valve in the air line between cars!

      •  Yes the spring would no longer be released by air (0+ / 0-)

        Locking the wheels.

      •  What's odd is this: they broke at the locomotives (0+ / 0-)

        I think it would difficult for the crew not to have set the brakes right, especially if you're on a grade and bedding down for the night. There's a brake line pressure gauge in the locomotive and the engineer can see if it's not holding or something else is wrong. One of the crew will usually walk the train too, just to see if everything is set right.

        The US and Canada usually require a "FRED" unit on a train, literally a "Flashing Rear End Device" that is attached to the rearmost coupler and is hooked to the brake line. It reports brake line pressure at the far end to the locomotive via a radio data link. I do not know if the MM&A has these. If you've ever seen a train the night go by and have seen a small flashing red light at the end, that's the FRED doing its job.

        What I've read so far is the cars uncoupled at the locomotives, and so the entire string ran down into town.

        More and more I'm suspecting the hand of man in this.

        And yeah, I know tarantulas don't really act like that at all, so no snarking, this is the internet damnit!

        by itzadryheat on Sat Jul 06, 2013 at 06:48:53 PM PDT

        [ Parent ]

        •  Well, I'm wrong on most of this. (0+ / 0-)

          The MMA, in a press release, states that the entire train rolled into town, locomotives and all, and that they were actually parked 6.8 miles west of town on a siding. They also state that the engineer had secured the train safely, and had gone to a hotel in Lac-Megantic for the night. This apparently is the usual routine as well.

          I think somebody broke into the locomotives, and got the train rolling. I can't see any other explanation for this to have happened any other way.

          And yeah, I know tarantulas don't really act like that at all, so no snarking, this is the internet damnit!

          by itzadryheat on Sat Jul 06, 2013 at 09:44:59 PM PDT

          [ Parent ]

      •  You mean like someone disabling the alarms (0+ / 0-)

        and other systems on board the Deepwater Horizon?  That must have been a VERY highly skilled team of eco-terrorists as getting onboard and sabotaging an oil drilling rig without being spotted would not be easy.

        No, if they were disabled most likely it was the company itself that ordered it done because they were acting up and it was easier to just bypass them rather than fix them.

        You have watched Faux News, now lose 2d10 SAN.

        by Throw The Bums Out on Sat Jul 06, 2013 at 11:14:43 PM PDT

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    •  Westinghouse air brakes engage if the air line (3+ / 0-)
      Recommended by:
      Zwoof, LilithGardener, itzadryheat

      Pressure drops. Locomotives provide the compressors.
      In theory, at least, if a car uncouples the brake hose pops free -they are separate from the couplers- and dumps the air, so the brakes engage.

      So if a train breaks in two, both halves stop.

      It is possible to use a handbrake (brake wheel seen on each car) to engage or disengage individual car brakes, but this seems to be something more.

      Thump! Bang. Whack-boing. It's dub!

      by dadadata on Sat Jul 06, 2013 at 01:19:37 PM PDT

      [ Parent ]

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