Correction: An earlier version of this story stated that Metro’s contract with Kawasaki Motors was for 528 railcars. The initial contract was for 428 cars and later amended to add another 100. This version has been corrected.

At a Kawasaki plant in Lincoln, Neb., a new Metro rail car is taking shape that changes the look of the system. (Lee Powell/The Washington Post)

LINCOLN, Neb. — In a low-slung building surrounded by cornfields, just a stone’s throw from the city airport, hundreds of blue-shirted workers are building the railcars that will whisk Washington area subway riders into a new era.

Inside this Kawasaki Motors manufacturing plant, the concrete floor shines. The whirring of drills and the popping of welding torches echo through the cavernous room. The buzz of activity is everywhere. All around sit Metrorail cars in various stages of construction.

Metro officials say the 7000-series cars being built here and set to make their debut Tuesday are a significant step forward in both safety and rider comfort. With their cool, brushed stainless steel exteriors, slip-resistant flooring, ergonomically engineered seats and digital signage, they are a quantum leap from the 1970s-era vehicles they will replace.

“This is absolutely a significant improvement for the region,” said Metro Deputy General Manager Rob Troup. “Getting these cars on the system will create greater reliability for riders.”

More importantly to federal transportation officials and the thousands of customers who will ride in them, the new cars will move Metro closer to addressing a critical safety issue. For nearly a decade, officials with the National Transportation Safety Board have urged the Washington Metropolitan Area Transit Authority to replace or retrofit the oldest cars in its rail fleet — the so-called 1000-series — which are considered dangerous because of their tendency to fold like the bellows of an accordion in the event of a crash.

The problem with the cars was first cited by federal investigators in 2006 after a crash at Metro’s Woodley Park station. NTSB investigators reiterated their concerns following the fatal 2009 Red Line crash that killed nine people, urging WMATA to retire the series. Of the 300 original 1000-series cars, 280 are still in service.

“Every 1000-series railcar Metro replaces with a new 7000- series railcar will provide a substantially higher degree of crashworthiness protection for riders based on the design information Metro has shared,” NTSB Chairman Christopher Hart said last week .

Metro had planned to deploy the new cars in January, but the launch was delayed in part because of a dispute with the Tri-State Oversight Committee (TOC) over safety testing. The committee monitors overall Metro safety. Late Friday , TOC chairwoman Klara Barashev said the panel had signed off on the launch.

The debut of the new railcars is a bright spot in what has been difficult few months for Metro. In January, a smoke incident in a tunnel near the L’Enfant Plaza station killed a 61-year-old woman and injured more than 80 others. The incident, which occurred during the final week of Richard Sarles’s tenure as general manager, raised questions about leadership and operations at the nation’s second-busiest subway system. It also raised concerns about whether the lax safety culture federal investigators cited during the investigation of the 2009 crash had improved.

Then, just a few weeks later, the search for Sarles’s successor was upended amid disagreement among Metro board members about what kind of leadership is needed to move the beleaguered agency forward. In addition to safety issues, the agency is struggling with financial difficulties, including fallout from a critical federal review that found significant problems with how Metro officials handled billions in federal grant money.

A successful debut of the new cars might bolster Metro’s efforts to persuade local jurisdictions to spend money for upgrades that will allow the system to run all eight-car-trains, boosting capacity.

The agency recently received preliminary approval to purchase an additional 220 railcars as part of the Kawasaki contract, but board members, who represent the District, Maryland, Virginia and the federal government, have not yet approved the $850 million needed for power and infrastructure upgrades that would enable the system to run all eight-car trains. Metro officials also are examining other scenarios that would cost less money.

For years, Metro officials put off replacing the 1000-series cars, first saying that a lease agreement prevented them from retiring the cars before 2014 — and then that they lacked the money to do so. But in 2008, as part of the Passenger Rail Investment and Improvement Act, Congress approved $1.5 billion in funding over 10 years to upgrade the system, including money to purchase new railcars. Two years later, Metro signed a contract with Kawasaki to build 428 railcars at a cost of $886 million. In 2014, Metro added an additional 100 cars to the order, pushing the overall cost to $1.46 billion for 528 railcars.

Expand, then replace

On Tuesday, the first eight-car train of 7000-series cars will make its maiden run on the Blue Line — a peace offering of sorts to riders of that line who have had to endure cuts in service to accommodate the new Silver Line. Metro has 24 of the new cars at its training and maintenance facility in Hyattsville, Md., and spokesman Dan Stessel said those will be rolled out in coming weeks. He declined to elaborate on the scheduling of the rollout.

Because Metro needed new railcars to be compatible with previous versions, it has never been able to take full advantage of advances in technology when it added cars to its fleet. The 7000 series represents a break from that. The railcars cannot be combined with cars of other series and must run as separate eight-car trains.

The hope is that the 7000s eventually will replace the older 1000-series cars, but until enough of the cars are built, they will be used to expand Metro’s current fleet, meeting the additional demand created by the opening of the Silver Line last summer.

This is the first time Kawasaki has built railcars for Metro. The company has built cars for systems in Boston and New York — the latter recently taking delivery of a new series of railcars.

“We’re very proud of this project,” said Joseph Reynolds, Metro’s chief of vehicle program services as he led a group on a tour through the vast factory a few months ago. “This is what the factory’s focused on. They’ve just finished an order for New York, but for the next few months, the focus will be on the 7000 series.”

New York’s subway system has more than 900 Kawasaki-built cars in its fleet of 6,300 — the oldest dating to 1984.

Kevin Ortiz, a spokesman for the New York system, cautioned against drawing any conclusions based on that city’s experience. “I’d be very leery about comparing our cars to those down in D.C. It’s a different system that runs under different conditions.”

Still, he said: “We’re happy with these cars.”

Each 75-foot railcar takes roughly three months to build and costs $2.8 million. Frames are shipped from Japan, but the remaining parts are manufactured in the United States. Here in Lincoln, workers will put together most of the parts that go into the car, including the dimpled stainless steel siding.

The factory’s vast campus includes the manufacturing floor as well as a 1,900-foot test track. The factory floor is a quarter-mile long. On one end, five partially completed 7000-series railcars sit on air pallets waiting to be shuttled to the next workstation. Signs with various codes and abbreviations show where they are in the production process.

“PASSED LEAK CHECK, O.K. TO C-LINE,” reads one. “NEEDS WATER TIGHTNESS TEST” reads another. The stainless steel siding on the railcars gleams under the factory lights.

The cars begin their lives at the far end of the factory where the end-underframes are assembled. The underframes serve multiple purposes — they are designed to absorb energy and prevent railcars from overriding each other in a crash, as happened in the 2009 Red Line accident.

The cars move through the building and fabrication process on elevated platforms, which enables workers to work simultaneously on the car’s bottoms, interiors and roofs. At each station, more elements are added: sound- dampening panels, thermal insulation, metal siding, roofs, wheels, seats, doors. There are 37 workstations spread between four lines. A separate building houses testing stations.

At one station, a worker wearing a heavy gray welding mask attaches brackets to the roof of a car. His welding gun pops and fizzes as orange and yellow sparks fly through the air. For a brief moment, he lifts the faceplate of his mask to check his work, then pulls it down and continues welding. The smell of smoke fills the air.

At critical stages in the manufacturing process, the cars reach “hold points,” where they are inspected by one of three full-time WMATA employees based in Lincoln to ensure the cars can meet Metro standards. Specialized robots do some of the assembly work; humans put together other elements.

Near the end of the manufacturing line, Troup steps into a car and animatedly explains what sets these cars apart from their ’70s-era predecessors. It’s not just the technology, he says, it’s how the cars are put together from top to bottom: The air conditioning units are on the top of the cars rather than the bottom, which Troup says makes them easier to repair.

Similarly, changes to the doors of the new railcars are designed to increase safety and reliability.

Unlike the much-maligned doors on Metro’s current cars, which are programmed to close even when an object is caught between them, the doors on the new railcars have a bounce-back feature. If something gets caught between them, that set of doors will partially reopen to allow the object to be removed. On current Metro cars, all of the train’s doors open when one set is affected, which can cause delays, Stessel said. The new doors also have fewer moving parts and don’t use screws, which have to be recalibrated after repeated openings and closings. Instead, they use magnets.

Troup points to the seating area for the train’s operator where the control panel has been redesigned. The gooseneck microphone has been repositioned so it no longer blocks the view of the operator’s screen. Designers have added foot and arm rests to reduce strain.

Unlike an automobile, which can be put together in a matter of hours or days, it takes three months to assemble a railcar. The wiring alone takes about 26 hours. When production is in full swing, the line here will turn out four cars a week, roughly 16 each month. If it is able to get additional funding, Metro hopes to have 748 cars — more than half of the system’s current fleet — delivered by 2020.

Local governments have said they won’t consider Metro’s expansion plans until the agency gets its finances in order.

And even as the new models move into service, Metro officials won’t say when they will begin retiring the 1000 series. But with the launch of the new series Tuesday, Metro is a step closer to that goal, officials said.

“It’s obviously satisfying,” said Troup. “That’s where the funding is important — that was the hard part. But the hard part has been done.”