After the fatal Red Line crash in 2009, Metro began running its trains in manual mode. (James M. Thresher/For The Washington Post)

Five years after a fatal crash on Metro’s Red Line, the transit agency said it will soon take a major step in recovering from the disaster by bringing back computer-driven trains, restoring a money-saving, smooth-ride feature that was part of Metrorail from its inception but failed catastrophically in 2009, causing nine deaths.

Starting early next month, in a process known as automatic train operation, computers will take over driving a half-dozen Red Line trains daily during non-peak hours, Metro General Manager Richard Sarles said. By March, all Red Line trains will be driven by computers, a move Sarles called “a milestone accomplishment.”

Drivers will remain in the train cabs, Metro officials said, and work is continuing on the Orange, Blue, Green and Yellow lines, with computer-driven trains scheduled to be operating in the entire subway system in three years.

“Symbolically, it’s an important sign of all the work we’ve done over the last four or five years to bring the [transit] system back to where it should be,” said Sarles, who plans to outline the timetable for Metro’s board of directors on Wednesday.

Automatic train operation, a feature of most modern subways, was shut down throughout Metro in 2009 after electronic flaws caused the worst calamity in the transit agency’s history.

The crash — in which a computer-driven train near the Fort Totten station plowed into a stationary train at an estimated 49 mph — was a watershed event for Metro, exposing what federal investigators said was a lax safety culture in the agency and prompting the resignation of then-General Manager John B. Catoe Jr.

Since then, with humans doing the driving instead of computers, passengers on America’s second-busiest subway system have routinely endured more annoyances than they did before the accident, including more train delays and jerkier rides.

Sarles, whose primary mission when he replaced Catoe the following year was to improve Metro’s safety awareness, had long resisted setting a public timetable for the return of computer-driven trains, saying he did not want to create an atmosphere in which managers and engineers involved in the project felt pressure to meet a deadline.

Now, after $18 million worth of engineering analyses, equipment purchases and pick-and-shovel labor along the Red Line, Metro said, the electronic problems that caused automatic train operation to fail have been fixed on that route.

Making the rest of the rail network ready for computer-driven trains by 2017, as planned, will cost an additional $33 million, officials said.

“I have not in the past given out a target date because I wanted the staff to get it right,” Sarles said in an interview. “I wanted them to cover their bases, review it, inspect it, then do it again, and have someone else come and look at what they did, so we’d be confident that we’ve put everything in place, and we’ll have a good start-up.”

Under automatic train operation — or ATO, as it is known in transit parlance — an operator sits in the cab of a train’s lead car. But the operator’s job is limited to opening and closing doors, making announcements and keeping an eye out for trouble on the tracks ahead, while an onboard computer does the driving.

The computer is designed to efficiently adjust speeds throughout a trip while precisely maintaining the proper distance from the train in front of it, smoothly braking and accelerating, and easing the train to a stop at exactly the right spot along a station platform, said Rob Troup, Metro’s deputy general manager for operations.

When ATO was shut down after the 2009 crash, Metrorail switched to “manual mode,” putting the operators at the controls.

Just as motorists have varied driving habits and skills, so do train operators. Some tend to speed up too quickly or slow down abruptly, jostling passengers. Because trains don’t always maintain the prescribed distance from trains ahead of them, operators often have to stop and wait between stations, eliciting exasperated sighs from riders.

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.”

The eight or nine seconds it might take for an operator to adjust position at a platform increases a train’s “dwell time” in a station, Troup said. He said those extra seconds, multiplied by the number of trains that don’t stop correctly, have a ripple effect along an entire rail line, making on-time performance more difficult.

Also, compared with ATO, inefficient manual-mode driving causes more wear and damage to rail cars, tracks and other infrastructure and consumes a lot more electricity, increasing Metro’s energy costs, Troup said.

But Metro’s faith in automatic train operation isn’t shared by everyone.

“I don’t think you should ever trust people’s lives to a machine,” said Carolyn Gamble, whose 23-year-old niece, LaVonda “Nikki” King, was the youngest of the nine victims killed in the 2009 crash. No matter how smooth the ride or how big the money-savings, “you can’t risk human beings to some computer,” she said. “It’s not worth it.”

A massive undertaking

Fixing the problem that caused the crash, and resuming automatic train operation, has been a massive undertaking, Metro officials said. It involves ripping out and replacing most of the rail-based electronics along 212 miles of tracks used by five subway lines.

The electronics, known as track-circuit modules, transmit critical data to the onboard computers that drive the trains. Essentially, each module is a stretch of track ranging from about 400 to 1,000 feet long, and each is wired with an array of electronic components. There are 902 modules on the Red Line alone, one beside another, along 64 miles of parallel tracks connecting the Shady Grove and Glenmont stations.

On June 22, 2009, a data-transmission failure occurred between faulty modules and Red Line train No. 112 near the Fort Totten station in Northeast Washington. As a result, the computer didn’t know that a train was stopped on the tracks ahead of it.

Train No. 112, with operator Jeanice McMillan in the cab, slammed into the rear of the other train, killing McMillan and eight of her passengers and injuring about 80 other riders on the two trains. In an emergency, the operator on a computer-driven train can apply the brakes. But McMillan wasn’t able to do so in time to avert disaster.

The faulty modules were a type called GRS Generation II, or “Gen 2s” in transit shorthand. In a crash-investigation report that was scathingly critical of Metro, the National Transportation Safety Board cited earlier Metrorail mishaps caused by the flawed modules and said Metro should have acted sooner to correct the problem.

Of the 902 modules on the Red Line, 810 were Gen 2s, transit officials said.

“Metro was on a collision course long before this accident,” Deborah A.P. Hersman, then the NTSB chairman, said at the time. “The only question was when Metro would have another accident, and of what magnitude.”

Now, workers have finished the laborious job of replacing those 810 Gen 2 modules with a new and better type of module, officials said. They said the new modules have passed federal safety tests, allowing for the return of computer-driven trains to the Red Line.

In an e-mail last week, Hersman, now chief executive of the National Safety Council, lauded Metro for its “resolve,” saying: “The return of automatic train operation marks an important station on [Metro’s] journey. It signals confidence in the remediation of the system failures that resulted in the collision five years ago.”

Troup said engineers also have built a computerized safeguard system designed to alert Metro to any problems with automatic train operation before the problems become critical. There was no such backup system when the crash occurred.

Computer-driven trains cannot start running on other subway routes until 1,611 Gen 2 modules have been removed from the Orange, Blue, Green and Yellow lines. So far, 900 have been replaced, Metro said, with the remainder to be removed by 2017.

The 11-mile first phase of the Silver Line, which opened in July, was built with a new generation of modules that are ready for use with computer-driven trains, the transit agency said.

Because each of those five lines shares tracks with at least one other line, Metro said, it will not start running computer-driven trains on the Orange, Blue, Green, Yellow or Silver lines until work has been completed throughout the rail network.

The Red Line is the only Metro subway route that doesn’t share tracks with another line.

Automatic train operation, which was a part of Metrorail when it opened in 1976, has been out of service long enough that only a small number of Metro’s 600 train operators are familiar with it, the agency said. Most of the 600 operators came on the job after the crash and have never sat back and let a computer do the driving.

Imagine the sensation of getting into an automobile and, for the first time, letting it drive itself — except an eight-car subway train, fully loaded, is 400 tons of metal and humanity.

“An engineer isn’t a psychiatrist,” said Troup, who is an engineer, “but we’re cognizant of the issue, and we’ll have training. We want people to feel comfortable.”

On the Red Line, supervisors will begin teaching operators about automatic train operation in early October, a Metro spokesman said. During that process, a half-dozen passenger-carrying Red Line trains will be driven by computers during non-peak hours, including weekdays from 9:30 a.m. to 3 p.m. and from 7 p.m. until the subway closes.

The spokesman, Dan Stessel, said Metro expects that all 170 Red Line operators will be familiar and comfortable with computer-driven trains by March, at which point all Red Line trains will start using automatic train operation during non-peak and peak hours.

“Even under ATO, we still need every one of our operators to remain vigilant, because stuff gets in the way of trains,” Troup said.

As Stessel put it: “There are some folks who might hear about this and think, ‘Oh, they’re going to have driverless trains.’ It’s important to keep in mind that every train will still have an operator, in October, in March and going forward.”