Metro announced a plan to fix its infrastructure, which will disrupt service for hundreds of thousands of commuters. This is how the plan will work. (Jenny Starrs,Claritza Jimenez/The Washington Post)

After decades of maintenance neglect, Metro next month will begin a huge subway rebuilding effort that will inconvenience nearly everyone who uses the system, with stretches of some rail lines closed for days, a reduction in late-night weekend service and a slowdown of trains throughout the year-long project, officials said Friday.

The transit disruptions will have ripple effects across the region as local governments and employers will be asked to make adjustments — whether it be changing HOV-lane restrictions to ease the anticipated increase in road traffic or allowing employees to work from home or modify their schedules.

“It’s what needs to be done,” General Manager Paul J. Wiedefeld declared in an interview before outlining his aggressive plan at a news conference.

“It’s going to impact people’s lives; it’s going to impact businesses, all of that,” he said of the infrastructure overhaul, which is expected to cause more commuting headaches for longer periods than any previous track work in the subway’s 40-year history.

Footage from a security camera at the Federal Center SW Metro station captured a fire that happened on the tracks on May 5, 2016. The fire was caused by an arcing insulator. (WMATA)

With the system addled by long-deferred maintenance — caught in a sometimes-calamitous spiral of breakdowns and other failures — a day of reckoning has arrived, Wiedefeld said.

The longest of five planned shutdowns will start Oct. 9 and last 24 days, involving a Red Line stretch from the NoMa-Gallaudet station to the Fort Totten station. The stations in between — Rhode Island Avenue and Brookland-CUA — will be closed.

Another shutdown, for 16 days beginning Aug. 20, will start at the Eastern Market station, on the Blue, Orange and Silver lines, and reach to the Orange Line’s Minnesota Avenue station as well as the Benning Road station on the Blue and Silver lines. Two stations in between — Potomac Avenue and Stadium-Armory — will be shuttered.

A week-long shutdown of the Blue and Yellow lines from Reagan National Airport to the Pentagon, starting July 12, means the Crystal City station will be closed. And an 18-day closure of the Blue Line from the Pentagon to Rosslyn will idle the Arlington Cemetery station for nearly three weeks starting Dec. 6 (except on Dec. 17, when it will open for the Wreaths Across America event at the cemetery).

The remaining closure, lasting a week, will be from the airport to the Braddock Road station, beginning July 5. There are no stations in between.

“I totally understand the inconvenience argument,” said Wiedefeld, now in his sixth month as Metro’s chief executive. But he said the work is desperately needed: “We cannot keep trying to Band-Aid over these issues. This is tough medicine. But we have to take it. And the sooner we take it, the better we’re all going to be.”

The year-long Metrorail rehabilitation plan includes 15 projects that will require the longest stretches of single-tracking and station shutdowns.

The overhaul, dubbed “SafeTrack,” includes 15 work projects, each called a “safety surge.” Starting in June, the surges will be conducted one after another along different stretches of the 118-mile system. Metro intends to replace, repair or refurbish almost every type of infrastructure.

The plan includes a moratorium on extended evening hours, as when the subway stays open after its normal closing time to accommodate late-night crowds leaving sporting events. And starting June 3, the system will shut down at midnight instead of 3 a.m. on Saturdays and Sundays, limiting transportation options for bar patrons and others.

Wiedefeld said that money for the work is already in Metro’s long-term capital-improvement budget and that the funds will be moved from future years to the current year to pay for the maintenance blitz. As for the cost, he said, “I don’t have a number on that yet.”

In addition to the shutdowns, 10 projects will involve closing one track for periods ranging from one to six weeks. That means trains headed in opposite directions will have to share one track in a work area. As a result of this single-tracking, commuters in an affected area will have to wait much longer for trains.

Much of the maintenance neglect, under previous generations of Metro leadership, resulted from public pressure to keep the subway operating at full capacity, for economic and convenience reasons, and from a push for Metro expansion by the transit agency’s directors and political leaders in the Washington area.

President Obama on Friday cited Metro as an example of the nation’s crumbling infrastructure and called on Republicans to back his proposals to boost spending on public works initiatives.

“It is just one more example of the under-investments that have been made,” Obama said. “The D.C. Metro has historically been a great strength of this region, but over time we have under-invested in maintenance and repairs.”

Some straphangers grumbled Friday but said they support Wiedefeld.

The disruption will be a “necessary evil,” said Augustine Carrillo, 39, a Red Line rider who commutes from NoMa to Metro Center during the week. “It’s either take the medicine in one big gulp or stretch it out for years.”

Dawn Keeler, a nurse from Falls Church, Va., said she favors the plan but hopes Metro will provide adequate bus service as a subway alternative. “There has been so much neglect and abandonment of this system for so long,” Keeler said. “I think this is a great idea. It’s necessary. We have to support this guy.”

Lauren Stern, 32, a Red Line commuter who works in the public health field, agreed with Keeler. “It’s going to be awful,” she said. “But what’s the alternative?”

Before unveiling the plan publicly, Wiedefeld on Friday briefed officials in Virginia, Maryland and the District on the plan. The three jurisdictions will have a month to come up with ways of coping with heavier road traffic and other impacts of the overhaul.

Officials who spoke publicly Friday were generally supportive of Wiedefeld’s effort but said they need to examine it closely and possibly suggest time changes­ for some of the more disruptive work. Wiedefeld said he will consider feedback from the officials over the next 10 days before finalizing the plan.

“Tough medicine for tough times,” said Montgomery County Council member Roger Berliner (D-Potomac-Bethesda), who is chairman of the Metropolitan Washington Council of Governments. “The entire region has suffered because of the failure over many, many years to make the hard decisions.”

Sharon Bulova (D), chairwoman of the Fairfax County Board of Supervisors, also backed Wiedefeld, saying the county will “assist in any way that we can.” D.C. Mayor Muriel E. Bowser (D) said: “I’m glad there is a plan. There is no doubt there is a need.”

Some D.C. officials, however, expressed concern for the thousands of District students who depend on Metro to get to school. About 75 percent of District schoolchildren attend schools outside of their neighborhoods. D.C. students can ride Metro and Metrobus free.

“I’m concerned about the timing of the proposed closures at Stadium-Armory and Potomac Avenue stations,” D.C. Council member Charles Allen (D-Ward 6) said in a statement. “The current draft proposes­ to close these stations August 20 – September 6, 2016. Those dates coincide with the first weeks of the new school year. Both of these stations are highly utilized by students and families travelling to school.”

On Capitol Hill, Rep. Gerald E. Connolly (D-Va.) said: “This unprecedented action reflects the severe damage wrought from decades of neglect for basic upkeep and safety that cannot be undone overnight.”

“Continuous single-tracking,” as Metro calls it, will occur between these stations: Franconia-Springfield and Van Dorn on the Yellow and Blue lines, June 4 to June 19; College Park and Greenbelt on the Yellow and Green lines, June 20 to July 3 and July 20 to July 31; Takoma and Silver Spring on the Red Line, Aug. 1 to Aug. 8; and Shady Grove and Twinbrook on the Red Line, Aug. 9 to Aug. 19.

Orange Line single-tracking will occur from Vienna to West Falls Church, Sept. 9 to Oct. 21; and West Falls Church to East Falls Church, Nov. 2 to Nov. 12 and March 6 to March 20; and on the Orange and Silver lines from East Falls Church to Ballston, Nov. 12 to Dec. 5.

The last prolonged single-tracking is set for the Yellow and Blue lines, Jan. 2 to Jan. 26, from Braddock Road to Huntington on the Yellow Line and Van Dorn on the Blue. But regular service will resume from Jan. 16 to Jan. 22 for the presidential inauguration.

The disruptions, whether from shutdowns or from single-tracking, will have ripple effects elsewhere in the rail system, slowing train traffic for miles around.

The biggest part of the infrastructure overhaul will be ripping up and replacing close to 50,000 wooden rail ties, Metro said. The ties, which support the metal rails, are used only outdoors. During the prolonged single-tracking, work crews will install thousands of pieces of new infrastructure, including rails, heavy-duty power cables and the connector assemblies used to attach cables to one another.

Faulty cables and connector assemblies have been implicated in several electrical malfunctions that have ignited Metro track fires. In one such incident, on Jan. 12, 2015, when smoke filled a tunnel near the L’Enfant Plaza station, the fumes enveloped a stalled train, killing one rider and sickening dozens of others.

The plan also calls for workers to seal about 1,100 water leaks in tunnels, eliminating much of the moisture that contributes to the smoky electrical meltdowns.

By forcing commuters to endure long-term disruptions, Wiedefeld said, Metro maintenance crews — working seven days a week, around the clock — should be able to revitalize the badly deteriorated subway by late next spring.

“It’s like a military operation,” he said. “It’s going to take a lot of effort and planning to get the labor where it needs to be, and the materials, the equipment — getting all the parts to move the way we want, on a scale that we’ve never done before.”

Overall, Wiedefeld said, the work that Metro hopes to accomplish in one year would take about three years under normal circumstances.

“A word of caution,” he said. “This does not mean that when we’re done, that the thing’s going to be a like a brand-new system.” Rather, he said, it will be like a 40-year-old subway that had been properly maintained over the decades. And keeping it that way will require a much-improved maintenance program in the future.

“We can’t keep doing it the way we’ve been doing it,” Wiedefeld said. “We’ve got to break that paradigm.”

Aaron C. Davis, Michael Laris, Luz Lazo, David Nakamura and Faiz Siddiqui contributed to this report.