Metro kicks the automatic train operation can farther down the road

On Thursday morning, WAMU’s Martin DiCaro reported that Metro is cancelling plans to go back to having computers operate its trains rather than humans who do it manually. Automatic train operations (ATO) keeps passenger wait times down and, more importantly, keeps them safe. Metro should be using the technology.

ATO works by having each train’s internal computer control its acceleration and braking. Another system, Automatic Train Supervision, knows where all trains are, and it works in tandem with ATO to speed up or slow trains down. ATO allows for more granular control of each individual train than what’s possible with human drivers

Giving control of train speed limits to a central system means trains are spaced evenly and that rides are smoother. When trains start bunching up, like they typically do with human drivers, the number of times your train stops in a tunnel or is held at a station goes up. So does the number of times it starts, then stops, then starts, then stops again.

Metro disabled automatic train operations (ATO) in 2009 after two trains collided at Fort Totten and killed nine people. One of the causes of the crash was what’s called “parasitic oscillation,” meaning some sections of the track “forgot” a train was there, which led to the tragedy.

Metro keeps delaying ATO’s return

To fix the issue, Metro had to replace 1,700 track circuits. Originally, the plan was to have that finished and to bring ATO back to the Red Line by October 2014. Later, Metro pushed the timeline back to April 2015. Then, later that year, Metro spokesman Dan Stessel said ATO wouldn’t return “any time soon” while spokeswoman Sherri Ly estimated it’d be back by 2017.

Now, Metro says it’s going to bring in a consultant to help determine “the best path forward as it relates to the deployment of ATO. If the expert signals that returning to ATO can be safely and efficiently implemented, WMATA leadership will then determine the next steps.”

What this tells me is that ATO won’t be back for years, if at all.

In a statement on the matter, Metro said that its decision to push back ATO is “Due to various factors, primarily driven by ensuring the safety of our wayside workers.” The concern here is that trains aren’t supposed to pass track workers at a speed faster than 10mph, and there isn’t a speed limit in ATO under 15 mph (unless they’re stopped, of course).

ATO is still a safer option than manual control

There are lots of reasons why ATO is safer than manually-operated trains. For one, ATO practically ensures that no train passes a red signal or is allowed to travel somewhere it’s not supposed to. There are ways for the train operator to override ATO, but those require purposeful actions by the operator; using ATO by default adds an extra layer of safety so both computer and operator are ensuring the train’s safety, and not just the operator.

Also, in manual mode, trains can go faster than the suggested speed limit on sections of track (there are two speed limits: the limiting speed, which is the max safe speed, and a regulated speed, which is typically slower but is better for keeping trains spaced evenly).

For example, the FTA implemented a 45 mph speed restriction between Grosvenor and Dupont Circle last year when they released their report about Metro’s electrical system. Without ATO, Metro has no way to force operators to adhere to this limit. Operators are continually reminded over the radio not to exceed that (and other) speed limits, but no technical system prevents them from driving faster.

Related to this, it’s good that Metro is concerned about track worker safety, but at the same time, this seems like an odd time to bring it up. The FTA’s monthly inspection reports note time and time again that operators consistently speed by track workers at speeds exceeding 10 mph. Operating in manual mode is not safer if the operators go as fast - if not faster - as automatic trains would.

Running in ATO is also critical to cutting down on the number of red signal violations Metro has each year. A computer doesn’t get tired, distracted, or zone out. With ATO, a train’s computer always obeys the track’s speed limits and stops at every red signal (under normal conditions— admittedly, it’s sometimes better to run trains by hand when it’s snowing, or when the tracks are extra slippery).

Just this last Saturday, a Green Line train ran a red signal at Naylor Road and entered one of the switches south of the station. If the train hadn’t stopped where it did, it could have hit another train, which was headed north toward the station. If ATO had been enabled, the southbound train never would have never run the signal.

ATO isn’t just a nice feature Metro - it’s how the system was designed to operate. In fact, the Rail Operations Control Center (ROCC) was originally housed in a room inside Metro’s headquarters, where there was barely enough space for the rail controllers, much less anybody else.

The vision for Metro was always that the system be extremely automated. Trying to have humans operate inside an automated system causes safety and throughput concerns. Proper maintenance and upkeep of those automated systems are necessary for ATO to be used, which in turn is necessary for Metro to have the ability to carry its riders safely on a consistent, reliable schedule.