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.
Posted by Dave Stroup at 8:03 PM