The maintenance program, which started last month and is expected to continue through at least April, is part of a larger Wiedefeld initiative: “Back2Good,” a project he announced last week to dramatically cut down on the number of rail car problems, which are responsible for 60 percent of the delays that customers experience. Wiedefeld’s goal is to cut those delays by 25 percent by the end of 2017.

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To achieve that, Wiedefeld is expediting the introduction of new 7000-series rail cars and retiring the problematic 1000- and 4000-series cars. But he also wants to find ways to improve the reliability of the 2000-, 3000-, 5000- and 6000-series cars that will be sticking around the system for many years to come.

The recently launched maintenance program is centered on a simple idea: Some of the most prevalent and disruptive issues on Metro’s rail cars might be solved with deceptively low-tech solutions.

“We look at the data. What are the issues that are driving the complaints?” Wiedefeld said. “Where do we have the problems?”

When engineering and maintenance staff looked at records of cars pulled out of service and subsequent repairs, they realized that problems tended to stem from four primary components of the trains: brakes, heating and air-conditioning units, propulsion systems and doors.

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So they took a closer look at those problems and tried to find solutions, Wiedefeld said.

Broken air-conditioners? Maybe there’s an easy way to keep their internal coils clean. Brake problems caused by small air leaks? Airplane repair crews have had an inexpensive fix for that for years. And perhaps, Metro staff wondered, there’s a way to make the doors on those legacy fleets a little more resilient to the wear-and-tear they undergo every day.

“It’s really just looking at the data … and reducing [the defects] as much as possible,” Wiedefeld said. “We will still have issues, there’s no doubt about it, but if we can just keep getting it smaller and smaller, it’s a better product for the customers.”

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Metro is scheduled to finish the preventive repairs on all its 2000-, 3000-, 5000- and 6000-series cars by April, but Wiedefeld warned that the process might take longer if work crews find additional defects that could be preemptively repaired before they cause problems.

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“That reflects the new culture we have here. We’re not putting out stuff that’s half-baked — we’re going to fix it, and it may take longer than we anticipate, but we’ve got to get it fixed,” he said. “We want to make sure that anything which can defect — the propulsion, brakes, HVAC system and pneumatics — we want to fix all of those things right away.”

Here are some of the solutions that Metro is employing to cut down on rail car breakdowns:

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1. Finally, a fix for #HotCars?

It’s a common problem during the summer: Metro #hotcars, those unbearably stuffy vehicles resulting from broken or barely-functioning air-conditioning units. When passenger complaints hit a fever pitch, those cars are taken out of service for repairs, which whittles down the number of cars available to run during peak service.

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Wiedefeld said he wants to use the winter to prevent some of those “hot car” situations before summer.

The performance of the air-conditioning units decreases once their internal coils become coated in dirt and dust. Maintenance crews told Bob Ernst, Metro’s superintendent of rail car maintenance, that they were having trouble cleaning the nooks and crannies inside the A.C. machinery because their long pressure cleaners were too unwieldy, sending out a single jet stream of water from the end of the metal rod that was difficult to maneuver.

So, at Ernst’s instruction, they designed and constructed new rods with pinholes poked into the sides. That way, once the cleaner was inserted inside the A.C. unit, water would blast in every direction.

Metro staff also thought about how they could keep those A.C. units cleaner for longer.

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Their final fix: New protective covers made out of a special flexible mesh that is impervious to water. (They performed a demo, pouring a bottle of water on the mesh and showed that none of it leaked through.)

But the mesh on the cover is just porous enough to allow air to flow through, meaning that the covers would be able to repel dirt and muddy water while still allowing the units to stay cool and ventilated.

“The size of the filter is such that only air molecules can go through — anything bigger than that, it will block it,” said Sachit Kakkar, Metro’s chief engineer for vehicles. “So any dirt or dust, it’s going to [get blocked by] this one, preventing the coil from getting dirty again.”

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“After six months, we just peel this one off, wash it, and put a new one on top of it,” Kakkar added. “So it’s going to keep the coils clean … so the cars can stay cool in the summertime.”

2. Air leaks get the aviation treatment.

Brake issues are a common problem that require trains to be pulled out of service — and Wiedefeld says that many of those incidents can be traced to leaks in the compressed air brake system.

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A small leak in the air system can put extra wear-and-tear on the compressor. A large leak can cause the air pressure to drop enough to cause the brakes to stay engaged, preventing the train from moving. Maintenance crews regularly check for leaks in the valves running along the train, but they can be difficult to detect: A tiny hiss is not always audible in a cacophonous train repair shop. Crews spray the air hoses and check for bubbles, but they can’t always see all sides of the piping.

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But a Metro engineer with a background in aviation pointed out that there is a much more exacting way to find leaks in the air hoses: an ultrasonic leak detector, a device commonly used on airplanes.

The handheld device listens for an ultrasonic frequency emitted by air leaks that’s outside the range of human hearing. Point the detector at a spot on the train’s undercarriage, and it tells you if there’s a leak, and how big its.

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Wiedefeld directed Metro to purchase 16 of the devices, at $800 apiece.

“It’s fairly inexpensive, it saves a lot of time. … it’s just a real smart thing,” Wiedefeld said.

Ernst notede that the leaks are now spotted much more reliably — and they’re getting repaired much faster, before they can turn into bigger problems.

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“You tighten it, you fix it, and that’s one less problem or issue you might have later on,” Ernst said.

3. A “first line of defense” against circuit breaker problems.

During Metro’s six-month process of bringing new components and fixes to trains, they will try to address some of the fleet’s propulsion problems by adding an extra component to each car’s high-speed circuit breaker.

The new component is an “arc chute.” It attaches to the circuit breaker and is designed to prevent stray current from shorting one of the train’s circuits, said Diane Holland, an assistant manager for engineering. Holland showed a circuit breaker that had been damaged because of stray current. When a circuit breaker fails in service, the train might have to be offloaded and sent to the repair shop.

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Arc chutes prevent the circuit breaker from failing by forcing the arc to divide into several smaller arcs, which cools off the circuit breaker.

“Because we’re dealing with high voltage, it creates a kind of arc,” Holland said. “The arc chute is there to dissipate that arc.”

“You don’t want the high current to go into the system,” she added, “so this is our first line of defense.”

4. A cure for the dreaded broken door.

It’s a shocking statistic: In a normal month, the doors on all of Metro’s trains open and close a total of at least 45 million times.

“There are 45 million opportunities for a door to go bad,” Kakkar said.

Metro’s maintenance managers stressed that the most significant cause of problems are people who try to push the doors open as they’re closing, along with people who lean against the doors. That kind of wear and tear, they said, can fracture the roller that allows the door to roll open and closed.

Still, Kakkar said, they’ve come up with a small fix that could cut down on some of the jammed door incidents: the nut. As cars are repaired in coming months, new nuts will be installed in the door mechanism that are made from a self-lubricating material and don’t need to be greased regularly.

5. A speed command testing system: “In two minutes, we are done.”

Holland said Metro has begun designing a new automated testing mechanism for speed commands. In prior year, workers had to manually test each cable to verify the command.

“This one, in two minutes we are done,” she said. “Versus having to take just to take the master controller out of the car — we’re talking about intensive work. And those cables are very delicate so we want to be careful not to create more problems.”

For now, the new speed command testing system is limited to 2000- and 3000-series models.

“But now that we have the design, we can move forward.”