Correction: An earlier version of this article incorrectly said that Metro will build a spiral escalator at Dupont Circle station for use in an emergency. Metro will install a spiral staircase. This version has been corrected.

The south entrance of the Dupont Circle Metro station could be closed for a year as three escalators are torn out and replaced with new ones.

Metro has not closed an entrance of a station for that long for escalator work in recent memory. Crews will work days, nights and weekends to try to speed the work at the 19th Street NW entrance, but officials said it could take a year.

“These escalators are the bane of every customer that goes through there,” Metro General Manager Richard Sarles said after briefing the board of directors at its meeting Thursday. “It will be short-term pain for long-term gain for customers We want to put new ones in there that will be more reliable and much more durable.”

Putting in new escalators at Dupont is difficult because the station is deep underground, and the entrance was built for two escalators, not three, leaving little work space. The south escalators are the least reliable of Metro’s 588 escalators, and their manufacturer is out of the escalator business, making it hard to find replacement parts, officials said.

When the work starts, Metro personnel will be on hand at Dupont’s north entrance on Q Street NW to help manage crowds and direct riders. Escalator mechanics will also be on call at that entrance to respond quickly to any mechanical problems.

A spiral staircase will be built this year in a ventilation shaft area at Dupont’s south entrance for use in an emergency. In July 2010, a report of smoke at the Dupont station caused a huge bottleneck as riders crowded one entrance.

The $12 million job of replacing the south entrance escalators, contracted out to Switzerland-based Schindler Group, is expected to start in the first quarter of next year. The escalator work is part of a larger contract to do work on the Red Line.

Metro depends on escalators more than other rail systems because its stations are far underground, and there are few staircases. It has more escalators than any other transit agency in the country. But keeping them operational has long been a problem.

Seventy-five percent of Metro’s escalators are more than 25 years old. Four manufacturers that once made parts for them are out of business, and the escalators haven’t been properly maintained over the years, Metro officials said.

Metro’s escalator and elevator repair division has long had troubles. In 1997, an investigation revealed that escalator maintenance records had been falsified. Nine escalator supervisors and top managers at the agency were fired, demoted or suspended.

In July, Metro opened the first of three new escalators at Foggy Bottom as part of a year-long project. The opening marked the first time in more than a decade that the agency has installed a new escalator at an existing station.

A second new escalator at Foggy Bottom is expected to open this month.