Correction: An earlier version of this article incorrectly referred to the National Museum of American Art. The correct name is the Smithsonian American Art Museum.

The next phase of a major Metro escalator replacement program begins Monday in downtown Washington as construction crews begin replacing the moving staircases at the Gallery Place station after more than four decades of use.

The project is part of a $179 million multiyear program to replace Metro’s oldest escalators, which transit officials say are reaching the end of their life span after years of carrying passengers down to Metro’s deep subways and back up, weathering rain, snow, heat and humidity.

The escalators at Gallery Place, built in 1976, are the first of 130 that will be replaced over seven years in a phased process that will take down the staircases one-by-one or in small batches, allowing for stations to remain open during the work.

On Monday, Metro will close the Gallery Place station’s entrance at 9th and G streets NW — near the Smithsonian American Art Museum and National Portrait Gallery — for about six months while a bank of escalators are replaced, the transit agency said. Station entrances at 7th and H streets and F streets will remain open.

Gallery Place’s escalators, which rise 28 feet, will be the first to be replaced across 32 stations, Metro said. The New Carrollton station is scheduled for the next replacement, with construction possibly starting in late May.

To install the new escalators, crews will demolish the existing ones and remove the parts using heavy equipment. Shutting down station entrances will allow the transit system to save about three months, compared with keeping an entrance open and shutting down one escalator at a time, the transit agency said.

Metro said that no more than 18 escalators throughout the system will be out of service at any time because of the project.

With 617 escalators, Metro said it operates the largest collection in North America.

The new escalators are being custom built by KONE, an Illinois-based company, and will include LED lighting and other safety functions.

According to a company statement, the replacement models include 117 KONE TransitMaster 180 escalators and 13 KONE TransitMaster 190 escalators, some of which rise to 98 feet.

The company is the same manufacturer as the first phase of the replacement program, which ended in November 2019 after nearly eight years.

Metro began the escalator replacement program after six people were injured in late 2010 when an escalator at L’Enfant Plaza malfunctioned after the Rally to Restore Sanity and/or Fear, an event thrown by comedians Jon Stewart and Stephen Colbert that drew more than 200,000 people. An oily brake pad was cited as a reason for an escalator’s sudden burst of speed.

Metro began the replacement program the next year, starting with the installation of three new escalators and a canopy at the Foggy Bottom station. The $176 million first phase replaced 145 escalators and rehabilitated 153 others with new motors, steps and handrails.

Canopies over several station entrances also were added to protect passengers and the escalators from the elements.