2.25.2010

Metro should end its "Safety Theatre"

Following the 6/22 crash, Metro management took some steps to help restore confidence in the safety of the rail system. These included switching train operation to manual mode, and placing Series 1000 railcars in the center of trains. As the NTSB hearings on Capitol Hill wrap-up, it's becoming clearer that both of these measures amount to little more than safety theatre.

First, let's discuss the sandwiching of the Series 1000 railcars. This seemed like a good idea at the time, logic tells you that placing the weaker cars farther away from a point of impact could be safer. In the days after the 6/22 crash, I wondered why Metro had not considered this option before. As it turns out, though, placing the Series 1000 cars in the middle of trains likely provides little benefit. Back in September, the Washington Post wrote that Metro officials admitted the action was little more than a public relations effort. At the time, WMATA fired back, citing an old scientific study (based on different train equipment) that sort of backed up their claim that it improved safety. Well, at the NTSB hearings we hear from a Metro engineer who admits that in high speed collisions (such as the 6/22 crash), the 'bellying' of the cars would do little. Metro spokesperson Lisa Farbstein has now retracted the agency's rebuttal to the Post's story. So, it's official, everyone agrees--bellying the cars does not improve safety.

One thing is for certain though, running mixed consist trainsets causes performance problems. Not only do you have issues with things such as the electronic displays in newer series cars, but you have braking and door problems. Communication between differing series railcars can be 'buggy,' so to speak, and does result in trains being taken out of service. Additionally, mixed consist cars make it more difficult for maintenance. Previously, it was possible to specialize maintenance based on the consist of trains on various lines (e.g. Series 1000 at Red Line yards, so on and so forth). Not so anymore. John Catoe made a point about the downside of mixed consist cars at the blogger roundtable in January. Bottom line, it's inefficient, causes service problems, and does nothing for safety. Now that Metro has admitted, under oath, that it does nothing for safety, they should end the program.

Now, the matter of manual operation. Under "manual mode," the train operator controls speed and acceleration of the train. Despite the name "manual mode," the train's operation is still governed by the Automatic Train Protection system. The ATP system does not permit a train from getting too close to another train, nor from exceeding the speed limit on a given part of the track. What's turned off is the Automatic Train Operation mode, which controls the speed and acceleration of the train. In ATO mode, the ride is smoother and schedules are easier to keep, as stopping and starting are computer controlled. For a good breakdown of Metro's safety systems, please refer to this post over at Greater Greater Washington.

The NTSB's line of sight tests at the site of the 6/22 crash show that it would have been difficult for the operator of the striking train to see the stopped train and stop in time. The train did not slow down because the ATP system failed to detect the stopped train. Had the train been operating in manual mode, it's unlikely the accident would have been prevented. It could be argued that the operator may be more "alert" in manual mode, however along most stretches of track, it's simply impossible for an operator to see a stopped train with enough time to stop (if the ATP system fails). Unfortunately, as it stands, the ATP system fails in an unsafe way. That will happen regardless of the train operating in manual or automatic mode.

As much as I want to say "do everything you can to improve safety," I don't believe that running in manual mode, or sandwiching the Series 1000 cars do anything for safety. I'll go out on the limb and say that both choices are merely theatre. Right now, it is possible that the ATP system could fail again. It's less likely that a failure would go undetected, but it could happen. When it does happen, it won't matter much at all what operational mode trains are in. Running in manual mode makes trains less efficient, the ride more jerky, and service levels poorer. One "advantage," I suppose could be that in the event of another collision, it would be the operator's "fault." That is, the operator would have been manning the throttle as it stuck another train, rather than the computer doing the work.

The real fixes to all of this involve replacing the Series 1000 cars as quickly as possible and getting an ATP backup system up and running. Along with this, of course, is the need for a better institutional priority on safety. Until the ATP backup system is up, the system will still be "unsafe." This is due to a poor design that completely forgets the concept of "fail-safe." If the system is going to be technically "unsafe" for a while, we might as well enjoy better and more efficient service.

13 comments:

  1. I can't believe that it took this long for someone to finally admit that moving the 1000 series cars was pointless. I observed this the same day it was proposed, and anyone with even a passing knowledge of physics should understand this. Yet apparently Metro thinks everyone on earth stupid enough to feel good about this move. Sadly it appears they were right.

    I actually believe that moving the 1000 series cars would be worse in a serious collission. If they are at the ends of the train, they will collapse and act as bumpers in a collision. Yes, the occupants of the end car would be effed, but it would protect everyone else. Which is exactly what happened on the 6/22 crash.

    On the other hand, if the 1000 series cars are in the middle, the occupants of them are still effed because they will collapse just the same. But everyone in the cars between them and the train they collided with get the full impact as well - likely resulting in much more carnage.

    It would be like having cars designed so the MIDDLE collapses in a collision, instead of the engine compartment.

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  2. By the way - I am not convinced that having a train full of 100% rigid, non-collapsing cars is ultimately better for safety.

    Automobiles used to be designed with rigid steel frames. What was discovered is that in a collision, the occupants of said automobile ended up through the windshield and 150 feet ahead of the car when they had a head on collision.

    Physics is still physics. What would have happened in the 6/22 crash had the trains been perfectly rigid? The force goes somewhere. The occupants would have been bug splats on the inside of the cars.

    Imagine such a collision in a tunnel, where it's impossible for the trains to derail, and the cars cannot collapse.

    If train riders don't wear seatbelts, then having cars that don't collapse is just trading one problem for another, probably larger one.

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  3. Now that .02% of Metro employees are now able to be fired w/o cause we'll see more responsible decisions being made!

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  4. Actually, from what I understand, the rigidity of the 1000-series cars isn't really a factor here.

    The main problem with these cars is their tendency to telescope in the event of a collision. Telescoping occurs when the top of the traincar detaches from the base, and the colliding train jumps on top, and subsequently rides along the base. This is "really bad" if you happen to be sitting in the bottom car.

    As somebody with an actual background in physics, it's not immediately obvious that this could still occur at the center of the train, as the strength of the couplings between cars would likely be the deciding factor. For now, I do think that the 1000 series cars are safer being placed in the middle of a set.

    Any crumple zone on a train would have to be quite large in order to provide any significant degree of protection, given the tremendous mass of a train. A head-on train collision is going to be horrific no matter how well the train is designed. The FRA's obsession with crashworthiness for passenger trains is part of the reason why our trains are far slower/uglier than anything found abroad -- the engineers used to joke that the Acela was a "high speed tank".

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  5. I'm Baaaaaaaack! Mooohahahahahaha! Mooohhahahahaha!

    Thanks for sharing, Jamie. Good stuff.

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  6. I wouldn't call Bellying the 1000 series cars "pointless," Jaime. Everyone was screaming at Metro to do something. So they did something. Even if it was a PR stunt - that doesn't mean it didn't have value.

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  7. The "Safety Theatre" is just a symptom of Metro's safety is a big joke attitude. Take for example the escalators, where a major reason for incessant breakdowns is Metro's staunch refusal to paint edge markings on the edges of the escalator steps. The side markings are there to warn people away from the edges of the steps. Instead, WMATA encourages riders to stand on one side instead of the center of the step. (Standing away from the sides and near the center of the step is recommended by the National Elevator Industry association (NEII), Elevator and Escalator Safety Foundation (EESF) and The American Public Transportation Association (APTA).) The problem is that the "push and shove" culture continues to the platforms and in the railcars.

    It would be a holy miracle if WMATA were to follow Third World safety standards as a matter of course.

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  8. Reading this is cathartic. The only thing manual operation does is give us a bumpy ride.

    During peak hours, the operators are adequately skilled and experience to do it right, but at all other times its somebody who thinks they are still driving a bus.

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  9. Jamie is absolutely spot-on. The 1000-Series cars will crush in the middle of consists, and it happened exactly like that in the relatively low-speed collision that happened at Falls Church Yard on November 29, 2009. A 5000-Series struck a 3000-Series rehab, and both consists had 1000-Series cars in the center. Guess which cars took the most damage - that's right, the 1000-Series cars. One telescoped in the usual way, and one bowed out sideways. While all the cars on both trains took some damage, only the 1000-Series cars suffered irreparable damage. That energy needs to find an outlet, and it found it in the 1000-Series cars when they crushed mid-consist.

    I'd recommend putting the 1000-Series back in dedicated consists, and put big warnings about the cars' lack of crashworthiness on them like cigarette warnings. That way people know what they're getting into when they board one of these rolling coffins.

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  10. The wreck looks terrible! I hope no one was seriously hurt from the incident. My thoughts and prayers go with the people affected.

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  11. It is very a pity to me, I can help nothing to you. I think, you will find the correct decision. Do not despair.

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