A Metro train is seen at Metro Center in this file photo. (Jahi Chikendiu/The Washington Post)

With the first phase of Metro’s Silver Line finally open, and with the transit system’s overall safety rating better now than it used to be in the eyes of federal officials, General Manager Richard Sarles said he has one major goal left before he retires in January.

And it has nothing to do with engineering work.

Over the next several weeks, in meetings with Virginia, Maryland and D.C. transportation officials, Sarles and his staff will be pitching a long-term, $7 billion spending program called Metro 2025. If the jurisdictions don’t agree to pay for the program, Sarles said, the centerpiece of Metro’s plan to ease rush-hour subway congestion — operating only eight-car trains on all lines during peak periods — will be unaffordable.

The part of the proposal involving eight-car trains would cost about $1.4 billion.

“That remains a top priority for us,” Sarles said recently, discussing what he hopes to accomplish near the end of his five-year tenure as chief of the country’s second-busiest subway system. If Metro doesn’t increase rider capacity, he said, “the region will face a problem at the end of this decade where the subway lines, especially the Orange and Red lines, will be overcrowded,” because of population growth.

“It will discourage people from using it to get to jobs” and will “slow down the economy in this region,” said Sarles, who lately has been outspoken about the Metro 2025 proposal, describing it as urgent almost every chance he gets in public.

Lawyers and financial specialists at the state, county and city levels have been discussing the proposal in private weekly meetings this month at the transit authority’s headquarters, and “our goal is to have agreement in principle by Thanksgiving,” said Metro spokesman Dan Stessel, noting that the agency is under a time crunch.

Metro has contract options to buy 220 new rails cars, which are critical to the plan. But without funding approval, the agency won’t be able to exercise the options before they expire next summer. And if that happens, Sarles said, the plan to boost peak-period rider capacity will collapse.

Virginia Gov. Terry McAuliffe (D) and D.C. Mayor Vincent C. Gray (D) have signaled support for Metro 2025, or at least for eight-car rush-hour trains. Metro 2025 also envisions major renovations to some rail stations to accommodate larger crowds, as well as the purchase of more buses and building more Metrobus-only road lanes.

As for peak periods on the subway, “we have issues because the rail cars are so full today,” McAuliffe said in February. “We need these eight-car trains.”

Whether Maryland will support the rail-car plan remains unclear, with a gubernatorial election soon to bring a change of administration there.

“All eight-car trains” has become a mantra for Metro officials. But it doesn’t mean all eight-car trains all the time. It refers only to peak periods — weekdays 5 to 9:30 a.m. and 3 to 7 p.m. — when passengers headed to work or returning home no longer would have to squeeze onto full six-car trains.

In a poll commissioned by Metro this month, the agency said, 300 Washington-area residents “were asked if they believe their elected officials should support the funding of eight-car trains.” Stessel said large majorities (87 percent in Virginia, 86 percent in Maryland and 79 percent in the District) answered yes.

Getting to that goal would be the last big accomplishment for Sarles, who joined Metro as its top manager months after a 2009 train crash on the Red Line killed nine people and exposed what federal officials said was a lax safety culture in the agency.

Among numerous recommendations at the time, the National Transportation Safety Board called for Metro to scrap its 300 oldest subway cars, known as the 1000 series, which were purchased in the mid-1970s. All those killed were aboard a 1000-series car. The old cars, built to outdated safety standards, are not “crashworthy,” the NTSB said.

As Metro’s rail network grew from its birth in 1976, the transit agency bought five more batches of cars over the decades — the 2000 series through the 6000 series — and now has about 1,100 cars. Before Metro can dump the 1000 series, it needs to buy replacements. And that process started five years ago as part of a plan called “Metro Forward,” the predecessor to the Metro 2025 proposal that’s now under discussion.

Whereas Metro 2025 focuses on expanding the transit system’s capacity, Metro Forward, for which regional funding was approved in 2010, was about improving the safety and reliability of Metrorail after the crash. Metro Forward included money for 528 new rail cars of the 7000 series, featuring advanced technology and safety features.

After a five-year process of contract discussions, design work and testing, Metro said it will soon direct the manufacturer, Kawasaki Rail Car, to begin mass production of the 7000-series cars. Eight of them are expected to begin carrying paying customers in January, Metro said, with the rest going into service over the next few years.

The 528 new cars will allow Metro to finally retire the 300 old 1000-series cars and also replace the 100 cars of the troublesome 4000 series, which were built in the early 1990s and have been chronically prone to breakdowns.

With 528 of the new cars on the way, Sarles wants 22o more, which would give Metro enough rolling stock to operate all eight-car trains during peak periods. Money for those cars, $614 million, is in the Metro 2025 proposal, along with $856 million for related infrastructure improvements, including opening more space in rail yards and maintenance facilities and boosting electrical power in the subway system.

For Sarles to achieve that goal, transportation officials would have to approve the spending in time for it to be included in the budget-making processes in Maryland, Virginia and the District next spring. If the funding isn’t locked down, the transit agency in late June would lose its contract options to buy the 220 cars from Kawasaki.

In that case, to eventually purchase new cars, Stessel said, Metro probably would have to start from scratch, perhaps with a different vendor, repeating a process of contract-bidding, design and testing that has lasted five years the first time around.

Currently during rush hours, only about half the trains on the Red, Orange, Green and Blue lines are eight cars long, while the rest are six cars. On the Silver and Yellow lines, where ridership is lower, all rush-hour trains are six cars long.

And peak-period commuters know how crowded those six-car trains can get.

“We can’t afford to wait,” Sarles told Metro’s board of directors recently. “Delays in addressing the full funding needs of the Metro 2025 plan, and specifically making progress toward eight-car trains, translates directly to lost economic growth for the entire region.”