Metro tests out its new 7000 series cars earlier this year at the Shady Grove station. The front of the cab is a distinct black, contrasting with the stainless steel of the car itself. (Bill O'Leary/The Washington Post)

In the offices of Metro transit engineers, where the native language is techno-speak, you’ll seldom hear words such as “confounding” or “confusing” or “shocking and surprising.”

But that’s how specialists working on the next generation of Metro subway cars, the 7000 series, describe a dispute with an outside safety overseer that threatens to delay the planned January debut of the spiffy new conveyances.

The disagreement, which arose last month, shows no sign of abating.

Lou Brown, the transit agency’s assistant chief safety officer, and Joseph Reynolds, Metro’s head of vehicle program services, say every component of the ­advanced-technology “7K” cars has been subjected to rigorous safety evaluations.

As Brown’s boss, Metro chief safety officer James Dougherty, put it: “The 7K safety and security certification program is not only compliant with existing [Federal Transit Administration] guidelines, but is also groundbreaking in how it has applied the principles” of the FTA’s “safety management system.”

Metro tests out its new 7000 series cars earlier this year at the Shady Grove station. An electronic sign flashes upcoming stops. (Bill O'Leary/Washington Post)

Klara Baryshev begs to differ. She chairs the Tri-State Oversight Committee, known as TOC, a three-member panel (representing the District, Maryland and Virginia) that monitors Metro’s overall safety.

“TOC has identified serious concerns with the process used by [Metro] to ensure that the 7000-Series railcars are safe and secure,” she told Dougherty in a letter.

Which prompted Brown, in an interview Tuesday, to abandon all jargon. “We’re at a loss to understand where she’s coming from,” he said.

Design work on the 7K cars began five years ago. The manufacturer, Kawasaki Rail Car, delivered four 7K cars to Metro early this year. Those four (which have been undergoing tests on Metro’s tracks for months), along with four additional 7Ks, are scheduled to start carrying fare-paying customers in January.

By 2018, Metro hopes to have 748 of the new cars in service.

Recent correspondence between Metro and the oversight committee on the subject of the 7Ks amounts to a volume of arcane transit-safety terminology — an alphabet soup of acronyms familiar only in the cubicles of local, state and federal transportation bureaucracies.

The gist of the exchange is: If you’ve been looking forward to commuting on a new 7K car in January, there’s a chance you might have to wait a while longer.

Here’s what’s going on:

Reynolds said that during the design process, every planned component of the 7K cars underwent a peer review by transit experts outside of Metro. “The specification goes out to the industry,” he said. “We want to know: Where are the possible faults? What are the possible hazards? What could go wrong?”

The propulsion and breaking systems, the doors, the interior and exterior lights, the computer that controls the car — “all of that was taken into consideration during the design process,” Reynolds said. He said potential faults were “engineered out” of the components or were “mitigated” to a point at which the likelihood of trouble was acceptably low.

Then one of each component was built, he said. Before the parts were assembled into one car, each part underwent extensive tests, in some cases for long periods, to determine whether the component was as safe in reality as it seemed on the drawing board.

“Every system gets tested to the extreme,” Reynolds said. “What will it take to break it? What will it take to make it fail?”

After all the components passed their tests, he said, they were assembled, and, thus, the very first 7K subway car was produced. Then three more were built — but without the components being subjected to the same stringent tests.

“That’s the way it’s done,” Reynolds said. “We’ve already validated the design. It’s like if you build an airplane, you test the components of the airplane, you validate that they’re going to perform according to your design, and then you go into manufacturing.”

Baryshev, the TOC chair, has a different take.

Under the oversight committee’s rules, with major projects such as this one, the procedure is for Metro to prepare a document detailing what its safety-testing regime will be, Baryshev said. She called it “the bible” — in this case, the 7K bible.

And Metro did that, she said. The 7K bible called for the extensive testing of each component that Reynolds described.

However, Baryshev said, by her reading of the 7K bible, Metro is required to conduct those tests on every component not of just one car but of the first four cars.

Metro “is choosing to verify one of these [components], from one car, and then issuing a certificate indicating that all four elements, for each of the four cars, have been certified,” she said in her Nov. 5 letter to Dougherty, the Metro safety chief.

“TOC is concerned that because [Metro] is not verifying the completion of all certifiable items for each individual car, an undetected design problem in the four cars may be repeated” in cars that are mass-produced in the future, Baryshev wrote.

She said Metro “must develop a corrective action plan” to conduct extensive safety tests on all the components of the three cars that were built after the first car – a process that Metro says would be very time-consuming.

Reynolds and Brown said Baryshev has misinterpreted the bible. “Shocking and surprising,” Reynolds called it, to which Brown added “confounding” and “confusing.”

They said they are awaiting another letter from Baryshev, requested last month by Metro’s board of directors, with a more detailed explanation of the oversight committee’s objection to Metro’s safety-certification process. Baryshev said Tuesday that the letter probably will be delivered to the transit agency this week.

Although it monitors the Washington Metropolitan Area Transit Authority’s operational safety, TOC has no enforcement authority. What happens if Metro and the oversight committee don’t come to an agreement?

The federal government, for now, is staying out of it.

“Decisions related to safety certification of the 7000 series rail cars are between the TOC and WMATA,” the Federal Transit Administration said in a statement. “It’s our understanding that TOC and WMATA are working to address outstanding concerns.”

Would WMATA put its first batch of 7K cars into passenger service in January without the committee’s approval?

Metro spokesman Dan Stessel hedged his response.

“We’re hoping to get a better understanding of what their concerns are,” he said, “so we can move forward together.”