One of Philadelphia’s major transit arteries, the trolley tunnel from 13th Street to 40th Street, is closing for 10 days starting Friday for its annual makeover, affecting the bulk of the riders who use the nation’s largest trolley system.

This is the seventh year SEPTA has closed the century-old, five-mile tunnel for repairs and preventative maintenance. Rather than complete the work intermittently, SEPTA opts to shut down the tunnel for a sustained period, which SEPTA spokesperson Andrew Busch said is “the most effective and efficient way to do a large portion of work in a relatively short period of time."

SEPTA holds the “blitz” in the summer because schools are out and it’s peak vacation season.

But that leaves the 62,400 people who use it each workday in need of an alternative during the shutdown from Aug. 9 to 19. Some are resigned to the inconvenience. Others see it as a welcome change of pace.

For Louise Langford, 49, who plans to walk from home near Clark Park to work at the Pew Charitable Trusts at 20th and Market Streets, it’ll be a chance to avoid daily encounters with a dingy tunnel where trolleys stir muggy summertime breezes and speed by so loudly that SEPTA workers need to cover their ears.

“It’s a perfectly lovely walk,” Langford said. The shutdown, she said, is a “really nice opportunity to walk above ground for once.”

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Every rider isn’t as sanguine about it as Langford.

Matthew Barry, 29, lives in Center City and works as a nurse at Jefferson Hospital. He recalled needing to walk to the Market-Frankford Line during one of the closures when he lived at 46th and Chester Streets.

“I remember in past years … it was very frustrating,” Barry said.

He added, though, that when the trolley worked, “it was pretty convenient.”

In fact, the tunnel is the main reason Philadelphia continues to have the country’s most extensive trolley network. SEPTA operates eight trolley lines, including two in Delaware County, on 68 track miles. Much of the country converted to buses decades ago, but they can’t navigate the tunnel’s tight turns, so in Philadelphia, trolleys got a reprieve.

Five trolley lines run through the tunnel, speeding riders beneath the congestion and traffic lights that plague surface transportation.

“It’s an asset that is critical to SEPTA as a whole," Busch said. “It has been a very key service area for us in a very congested area in our system.”

Workers operating in shifts around the clock will be tasked with a variety of repairs and improvements, including replacing a segment of track west of 33rd Street and a track intersection. They will also add energy-efficient lighting, test backup generators, and replace wooden boards that secure overhead wire to the tunnel’s ceiling.

Trolley riders through Center City will be asked to use the Market-Frankford Line, instead. From there, they can board trolleys for Routes 10, 11, 13, 34, and 36 at 40th and Market Streets. There will be a free interchange set up so passengers continuing their journey won’t need to pay extra for their trip.

SEPTA ambassadors and transit police will be at the 40th Street El station to ensure the free interchange isn’t being misused by fare evaders.

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The ambassadors, who will be wearing yellow safety vests with the SEPTA logo on the back, also will help people unfamiliar with the subway.

SEPTA does not plan to run additional buses or alter the El’s schedule to accommodate displaced trolley passengers.

Paola Cruz, 22, uses the trolley in her commute from Cobbs Creek to Old City. It’s easier than transferring to a bus, she said. Because she is originally from New York City and commuted 30 minutes on the subway one-way every day to get to her middle school, the trolley shutdown doesn’t worry her.

“I’m used to all the delays, transit changes, the work being done," she said. "It’s just another day.”