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Transportation United States

Washington DC To Return To Automatic Metro Trains 179

Bruce66423 (1678196) writes with news of interest to anyone with reason to ride mass transit in the U.S., specifically on the D.C. Metro system: After a crash some five years ago, automatic operation was abandoned. Now however replacement of 'faulty' modules means that moving the whole system on to automatic operation can happen. One quote is depressing: "And because trains regularly lurch to a halt a few feet short of where they should be at platforms, Metrorail riders have grown accustomed to hearing an announcement while they're waiting to board: 'Stand clear. Train moving forward.'" That never happens on the London underground with human operators? What's wrong with American drivers?
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Washington DC To Return To Automatic Metro Trains

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  • by Anonymous Coward

    Never seems to happen in New York. What's the problem in DC?

  • by Jmstuckman ( 561420 ) on Saturday September 20, 2014 @05:25PM (#47955875) Journal

    > What's wrong with American drivers?

    DC's metro trains were designed to be operated automatically the vast majority of the time. Hence, the acceleration and braking systems were optimized for automatic operation (as opposed to manual operation) and it is difficult for a human driver to control the train's movements precisely and smoothly.

    • by NormalVisual ( 565491 ) on Saturday September 20, 2014 @07:24PM (#47956323)
      Hence, the acceleration and braking systems were optimized for automatic operation (as opposed to manual operation) and it is difficult for a human driver to control the train's movements precisely and smoothly.

      I have a perspective on this that most probably don't, as I was a monorail driver at Disney World for a number of years. Contrary to what some might imagine, the current Bombardier Mark VI trains there are not attractions but are in fact full-up transit vehicles, and Bombardier continues to sell them as such (although with different bodies and newer electronics). If D.C.'s trains handle anything like ours did, I can understand why some of the drivers short-stop or otherwise have problems.

      Our Mark VI trains were originally designed to accommodate automation as well, but I don't think this in itself really is a factor. More importantly, each train had its own "personality" and handled differently, and all of them would take between one and two seconds to respond after an input was commanded except for E-stops, which instantly opened the relay contactors and applied air to the friction brakes. One train might be ultra-responsive (relatively) to the throttle and have really tight brakes, which made it easy to drive and predict stopping distances with great accuracy. Others would act like your control inputs were more of a suggestion than a command, necessitating that you be looking a little ahead of where you actually wanted to be in order to stop where you were supposed to. We had some drivers that had difficulty dealing with that, and would often blow their stops by a couple of feet or so on a train with loose brakes, or would stop short if they were in a tighter train that didn't require so much anticipation of its behavior. I don't think I ever had a short stop, but did have trains "slide" on me a few times and missed the stop by just enough to have to back up a couple of inches to get lined up with the gates.

      I would imagine transit trains everywhere exhibit similar unique peculiarities, and the only consistent way to deal with it is for the driver to be ultra-conservative, which can lead to the occasional short stop. It's not so much a problem for an automation system that can directly respond in milliseconds and isn't being moved between trains with wildly varying performance characteristics.
      • BART trains (in the SF Bay Area) have some peculiarities which do seem to be related to the partial automation. The trains frequently have to be 'repositioned' on the platform, but it's apparently* because the door mechanisms don't always engage. If the driver scoots forward a bit and stops again, then the doors open normally.

        *I think this because some drivers make announcements implying it's so, e.g. "sorry folks, we have to reposition to get the doors open."

        • by NormalVisual ( 565491 ) on Saturday September 20, 2014 @10:01PM (#47956903)
          Disney's trains were retrofitted in the mid/late 00's with a similar system. There are three optical switches that all have to be aligned with corresponding places at the station, otherwise the driver is unable to open the doors. It was fairly easy to only get one or two of the sensors in place, requiring the driver to move the train a couple of inches forward or back to get his doors open. It's gotten to be a real headache for today's drivers, since the new rules Disney instituted after the accident in 2009 require that *any* reverse motion of the train be set up by the central coordinator and visually cleared by an independent spotter beforehand, even if it's only to back up an inch.
      • by kriston ( 7886 )

        Washington DC Metro and San Francisco BART are very similar systems and were designed from the outset for fully automatic operation. The platform position errors are learned by the system and corrected over time, and this calculation also measures the weight of each car.

        The real challenge is that under crush loads the system tries to get a good idea how much braking force to apply with the extra weight of the passengers, but often gets the calculation wrong because even though the system "knows" how much e

        • but often gets the calculation wrong because even though the system "knows" how much each car weighs, people sway back and forth as the vehicles slow down and we undershoot the platform.

          That's good that it's conservative like that, but does it actually bring it to a complete stop short of the mark? There have been times when I've been driving a full train that it slowed a bit more aggressively than I would have expected, but it was easy to just modulate the brakes to hit the mark without stopping short
          • Then again, our trains were substantially lighter (about 50 tons empty, 80 tons crush load), so I'm sure it was easier for us to deal with the varying inertia.

            Up until the point where a bigger brake won't help, you can solve this problem completely with bigger brakes, which provide consistency. Well, it works for everything but trains, so I don't see why not trains too.

          • by ihtoit ( 3393327 )

            that's very light for a commuter train, our tram system uses four-segment cars that weigh over 120 tons dry. Those things seldom go over 35mph. London's underground trains are 27 tons *per car*. Dry. And each train has six of them.

            • Yes, they are quite light. We have six-car trains with a capacity of 60 passengers per car, so the capacity is comparable, but they've got composite bodies over a steel subframe, which saves a lot of weight. They don't have to be really heavy since it's an elevated system with no chance of interaction with roadway traffic, and owing to their configuration, they deal with high winds quite well without needing the extra weight just to keep them on the track. Additionally, there are some grades on the syste
              • by ihtoit ( 3393327 )

                speaking of weight, the DLR trackbeds had to be reinforced for the Olympics not because of the extra weight of passengers so much, but because the original two-car trains needed to be upgraded to three car D2007 trains which were nearly double the dry weight - and would have killed the Victorian-era viaducts the DLR ran over

        • Washington DC Metro and San Francisco BART are very similar systems and were designed from the outset for fully automatic operation.

          I still don't see why this should be a problem. As the article pointed out the London Underground operates flawlessly in this regard. There's a mix of trains there. All trains can be manually driven. Some lines are now pretty much fully automatic with the driver only required to press the button to start the trip to the next station.

          Neither manual not automatic operation seems

      • More importantly, each train had its own "personality" and handled differently, and all of them would take between one and two seconds to respond after an input was commanded except for E-stops, which instantly opened the relay contactors and applied air to the friction brakes.

        Don't we have machine learning and adaptive control for that? These things should still be easier for a computer than for a human. Even momentary weight estimates could work based on the most recent history of acceleration and engine power. You shouldn't even need full automatic control; If you absolutely need humans in control, you could still give them semi-auto modes. Apollo LEMs had those in 1969 already. Why does it have to be full-auto or full-manual?

        • Don't we have machine learning and adaptive control for that? These things should still be easier for a computer than for a human.

          I'm not disagreeing with you. I didn't design the train control system. :-) There was so much on our trains that the drivers really shouldn't have had to deal with, and I found it kind of ironic that the Orlando International Airport terminal shuttles had more smarts than our trains. As of 2012, Disney had concrete plans in place to finally put automation on the trains, wh
  • by Anonymous Coward on Saturday September 20, 2014 @05:27PM (#47955887)

    For example the central line has been automated since the 90s. Drivers there just to go on strike

    • For example the central line has been automated since the 90s. Drivers there just to go on strike

      +1 internets. So true.

      Though in actual fact the drivers do serve some other purposes. Parts of the subsurface system (Central, District, Metropolitan, Hammersmith and City) are open to the air or just plain above ground. The drivers are needed in case there are unexpected obstructions on the line. Also, since none of the stations are designed for it (unlike the new metro line in Paris), the drivers are needed to make sure that the train is safe to leave and no passengers are stuck in the doors and so on.

      The other, important purpose it to make sarcastic announcements when the train gets stuck at a signal, which is something they do excel at.

      • The drivers are needed in case there are unexpected obstructions on the line.

        If that were correct how would the Docklands Light Railway operate above ground without any drivers at all? The sad reason that drivers are needed is because of the unions. They automated the Victoria line years ago (1960s) but the unions threatened action and the resulting chaos that a drivers strike would have caused on the lines which were not automated forced them to keep drivers on each train even though they are completed unnecessary.

        • If that were correct how would the Docklands Light Railway operate above ground without any drivers at all?

          You are right in part: the late and IMO not lamented Bob Crow has been responsible for a lot of stupidness by running that union.

          However, the subsurface lines share infrastructure with the surburban railways, whereas the DLR is essentially a closed system.

        • by ihtoit ( 3393327 )

          DLR operates without drivers because it isn't subject to london transport rules that say that a train shall be manned at its head at all times. Most DLR carriages do, however, carry what are referred to as train captains, who have key access to control panels at either end in case they're needed (they also control the doors but normally the SELTRAC system controls the drive system subject to door safety interlocks engaging).

      • The other, important purpose it to make sarcastic announcements when the train gets stuck at a signal, which is something they do excel at.

        The NYC system has this semi-automatic. They have about 5 different announcements claiming conditions like "held for train traffic ahead", "held by the dispatcher", etc, all recorded by the "50s announcer guy" ("You may know me from such announcements as 'The White Zone is for Loading and Unloading Only, No Parking'"). When the train is stopped for any reason, the driv

      • the drivers are needed to make sure that the train is safe to leave and no passengers are stuck in the doors and so on.

        Depending on the size of your trains, these things are best done by a bunch of cameras keeping an eye on the full length of the train, obstruction detectors in the doors themselves, and platform staff. The cameras can be watched from a central location (could be central to the city, the line or to the station) with one person watching the complete train and keeping an eye on the crowds on the platform, while the obstruction detectors can give off an alarm to the automatic train control system and/or the sta

  • by Animats ( 122034 ) on Saturday September 20, 2014 @05:33PM (#47955905) Homepage

    The Red Line crash was not computer-related. The signalling system for the Washington Metro is a classic electromechanical relay-based system. Just like the New York subways. The Red Line crash was caused by a failure of a track circuit for detecting trains, trackside equipment using an audio-frequency signal sent through the rails and shorted to the other rail by the train's wheels. [ntsb.gov] All those components are pre-computer technology.

    As with most railway systems, manual driving isn't enough to prevent collisions, because stopping distances are often longer than visual distances. That was the case here.

    The Washington Metro had been sloppy about maintenance of trackside equipment. They do have a central computer system, and it logs what the relay-based signal systems are doing, although it can't override them. They had logs of previous failures, and should have fixed the problem.

    • by Anonymous Coward on Saturday September 20, 2014 @06:22PM (#47956079)

      In fact, one of the trains involved in the crash was being operated in manual mode rather than automatic mode, contrary to policy at the time. Though unrelated to the underlying failure of the track circuits, one of the immediate causes for the collision happening at that failed circuit was that the train in manual mode had been moving slower than normal automatic trains would normally move across it.

      Basically, the regular speed commanded by the automated system on that track is 55mph. When crossing the faulty circuit, the speed command becomes 0 and the train slows (but does not trigger emergency braking). For automatic trains, before the train came to a stop, momentum had already carried it forward into a working circuit and resumed normal speed commands. In the 2009 crash, the struck train was being manually operated below 55mph. Because of this it took less distance for the operator to respond to the 0 command and stop the train. The train came to a stop entirely within the faulty circuit and became effectively "invisible." The train behind it was commanded by the system to proceed at 55mph and didn't have time to slow very much once the stopped train came into view and the emergency brake was activated.

      (Even if the collision had not happened at this spot, the underlying cause was completely overlooked by Metro and a collision would have happened eventually - perhaps more severely, if in a tunnel, or less severely, if on straight track with a long visual distance for emergency braking. The same failure happened in a tunnel in 2005, almost resulting in a collision, but Metro failed to fully investigate and understand why the problem happened.)

      • by kriston ( 7886 )

        No. Both trains involved in the crash were in automatic mode. The only time in manual mode was when the unfortunate soul operating the striking train applied the emergency brake.

  • DC's subway system uses a patronage policy.
  • While the traditional London Underground has drivers, that's pretty much just because the powerful union in charge won't let them be upgraded to be driverless. We've had reliable, safe driverless trains for over 25 years on the 45-station Docklands Light Railway in the East of London.

  • That never happens on the London underground with human operators?

    Are you asking a question or making a statement? Hello, editors?

    Now however replacement of 'faulty' modules

    Is that what they call human drivers now?

  • Americans.

    Had to be said :)

  • That never happens on the London underground

    Neither it does on Paris' underground lines, whether automatic or not

  • by mark_reh ( 2015546 ) on Saturday September 20, 2014 @09:33PM (#47956825) Journal

    I always wondered why they had drivers. How hard is it to start and stop a train? I asked one of my Japanese coworkers why he thinks they have drivers, what with all the technology in Japan and all, and his reply was very insightful: "they have drivers so they can blame/fire someone if something goes wrong".

    THAT is why trains have drivers.

    • by kriston ( 7886 )

      No. They have operators who operate the doors and ensure the train does not leave the station with someone hanging out of a door, or other kind of emergency situation.

      Are we having a serious conversation here? If not, I'll bail out now.

      • Are you suggesting they can't detect when someone is preventing a door from closing completely by any means other than a person looking?

        Interterminal trains in airports all over the world operate without human operators.

        Did you know that automatically flushing urinals use sensors that detect the presence of someone standing in front of them and then flush when that person has moved away? No, it isn't a camera with someone on the other end paid to watch you pee and then flush for you when you're done- (well

        • by kriston ( 7886 )

          There certainly is an interlock that prevents the train from leaving the station unless all doors are closed. The automatic system takes this as a cue to release the brakes and depart the station

          As built, the system was supposed to have automatic doors that would open like elevators if someone got in the way. This made operations difficult so the doors now just keep trying to close like every other system.

        • Are you suggesting they can't detect when someone is preventing a door from closing completely by any means other than a person looking?

          An obstruction interlock can certainly detect an arm or a leg, but if you set it sensitive enough to detect loose fabric (say, a scarf or a hanging sleeve), it'll be sensitive enough that thermal expansion will cause false positives and negatives.

    • by vix86 ( 592763 )
      If you lived in Japan like I have, then you should know the answer to this.

      1. Japan values customer service. Having a face be there to control the train or open/close the doors makes the service "friendlier." Also, if they removed the staff and made it automatic the old people would complain.

      2. "Its how its always been done so why should we change."
    • by jbssm ( 961115 )
      No, they have drivers because this is a potentially dangerous environment, with many people around, and protecting peoples lives takes so many implications that it's difficult to pt in an algorithm.

      What if someone jumped to the line, or fell in the line, would the automated system be able to see it and break?

      What if the doors closed with someone coat on it and that person was being dragged by the metro? Would the automated system be able to detect that?

      My point is that: 1 - Sensors and processing are st

  • by kriston ( 7886 ) on Saturday September 20, 2014 @11:45PM (#47957183) Homepage Journal

    The automatic system was fine for nearly 40 years. The upgrade process killed nine people and injured 80 and caused a safe system that ran reliably for nearly 40 years to run in "manual" mode for five years because of a maintenance error.

    Several depositions from railroad workers who were tasked with upgrading Metro's nearly 40-year-old system mentioned a real problem. The signals were "bobbing." This happened because the older signal system was being replaced with a different vendor's technology in two phases with catastrophic results.

    In phase one, the lineside signal cabinet equipment was replaced but the original track sensors were left. In other cases, it was reversed: the track sensors were replaced but the lineside signal cabinet equipment was original. In both cases the vendor was different and not totally compatible.

    Naturally, as we would expect, the two different vendors' equipment was not interfacing perfectly. This caused signal "bobbing," where track occupancy would "bob" from red to green repeatedly. Trains would vanish from the system. Phantom trains would appear in the system.

    This massive oversight reported in the depositions wasn't really taken seriously in the press nor by the accident investigation. From this point of view, the system failed due to incompatible equipment made to interface in order to save money and service disruptions. They didn't interface properly, and people died as a result. Nobody seems to care about what appears to be the real problem: incompatible vendors made to interface to save time and money.

    But we now have faster trains with shorter headways that sometimes fail to stop at the correct spot in stations, so we have that going for us. At least the lineside cabinet equipment and track sensors are now from the same vendor, eliminating the problem that killed those people and put hundreds of thousands of others at risk for a couple of years until that deadly day in 2009.

  • The Copenhagen Metro (Score:2, Interesting)

    by Anonymous Coward

    In contrast, the Danish Copenhagen Metro went into operation late 2002. After extensive teething problems during the first years of operation, I was very surprised at just how well this driverless system now functions. Additionally, the design and architecture is extremely futuristic. The above ground sections linking the CBD with the airport are more reminiscent of scenes from Star-Trek. Though quite small (2 lines), it is currently undergoing a city-wide expansion phase. In cases of extreme winter weather

    • I've only been on the Copenhagen subway once, but I remember that the stations did have glass walls between the platform and the rail, with doors matching the doors on the trains. Not much error margin or people could not get out or in, and the few stops I was on the train it stopped perfectly every time.

  • by mha ( 1305 ) on Sunday September 21, 2014 @03:19AM (#47957781) Homepage

    I live in Nuremberg, Germany. 2 of 3 subway lines are fully automatic. They run much more often than with drivers, and this is actually MIXED operation: the third line, that is still driver operated, shares the tracks on the middle section through the city. Nuremberg was the first city to have such a mixed-mode subway.

    They are on time for the most part, stop within a few cm of where they are supposed to each time, and are just a normal part of life. I've read about an occasional hiccup but never experienced one myself, and I don't think it's more than it would be in the "old system". The biggest stops were due to worker strikes, not technology issues. They didn't lay off anyone, by the way.

    Anyway, it is just unexciting business as usual for me any more, nothing special.

    Video (1min): https://www.youtube.com/watch?... [youtube.com]

    http://www.railway-technology.... [railway-technology.com]

    http://en.wikipedia.org/wiki/N... [wikipedia.org]

    • Vancouver, BC, Canada has Skytrain, which is fully automated. No drivers on any of the cars at any time. They can be driven manually at the yards and in emergencies, but never as a part of normal operation. The system is so reliable that the biggest problem they have is people getting impatient with short delays and forcing the doors open to walk down the causeway to the next station. Then they have to shut off that section of tracks until everyone is off, which makes the delay much longer.

      http://en.wikiped [wikipedia.org]

  • This *does* happen on the London Underground - but only those lines that still have drivers. The Victoria and DLR have been fully automatic for decades, the Northern line has recently been upgraded to a fully automatic system. These lines, to my knowledge, always stop at the correct point on the platform.
  • Since London Underground trains are all the same length, they're all pretty much the same weight (160 tonnes give or take twenty for passengers using the D78 stock electric units in trains of six cars). For the driver, this means that standing on the brake when you hit the brakepoint (or letting the e-brake take it when you hit the warning point) stops the train on the same spot every time: within a foot or two and ALWAYS behind the stopgate at the far end of the platform. Experienced commuters know where t

  • This comment [slashdot.org] is actually interesting, not redundant...

  • Tokyo was rolling that out when I wrapped my commercial duty tour in 1978. The recently finished Oedo Line, newest in the system, runs on linear induction motors. That means no more overhead network of catenaries to deliver power.

  • This is actually one of those things I thought about a lot while riding the red line metro to and from work each week.

    I've noticed that among other things, there seem to be a couple of metro drivers who like to operate the trains at speeds as fast as possible between stops, rather than just pacing it more sensibly. They'll rapidly accelerate, headed westbound out of a station like the Bethesda or Friendship Heights location, only to wind up stopping in the middle of the track someplace before the White Flin

  • I relocated her in '09. This is the least friendly subway system I know of... and I lived in Philly, and Chicago, and am familiar somewhat with NYC, and a little with Boston's, and have even done the BART a couple of times.

    For no known reason, they'll wait anywhere from 5 to 40 seconds *after* they come to a complete halt to open the doors. I presume this is some pseudo-Saftty thing (also, presumably dreamed up by someone who's never ridden a subway). Then they don't seem to be looking - it's close the door

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