Metro officials said today they are considering closing the southern entrance to the Red Line’s busy Dupont Circle station for up to a year to replace all the escalators on that side.

General Manager Richard Sarles said the highly unusual plan could get underway during the first few months of 2012. Sarles and other officials said the transit authority would go to great lengths to make sure that while all the escalators on the 19th Street NW side are out of service, the escalators at Q Street NW, on the north side of the station, would remain in service.

They said riders also could consider using the Farragut North station at Connecticut Avenue and L Street NW, a few blocks south of Dupont Circle. (The ceiling repairs at Farragut North should be done before the Dupont Circle project starts, Metro spokesman Dan Stessel said.)

While Metro’s escalators are notoriously unreliable, the usual strategy is either to make quick fixes when they break down or spend months rehabilitating them. It’s unusual for the transit authority to install completely new units.

At the start of 2011, Metro began the year-long replacement of the three escalators at Foggy Bottom station on the Orange and Blue lines. One escalator has been replaced, and a second new unit is scheduled to enter service in the next several weeks. Installation of a staircase and a canopy is also part of the project.

But at Foggy Bottom, which has only the one entrance on 23rd Street NW, the work had to be done while riders continued to use the remaining escalators.

For several reasons, the Metro officials said, they are considering a different strategy at Dupont Circle. The fact that there are two entrances gives them some flexibility in closing one. But they also said the design of the south side entrance creates some special challenges that lead them to favor a complete shutdown for the escalator replacement.

The three escalator units are much longer and heavier than the ones at Foggy Bottom.

Plus, they said, the Dupont Circle escalators are closer together than those at Foggy Bottom. Even if they chose to keep the entrance open as much as possible, there still would be lengthy periods — perhaps months — when the entrance would need to be blocked off while new machinery is installed.

Without a complete shutdown, officials estimate it might take several years to complete the replacement under normal working conditions.

But they conclude that by completely shutting the entrance for the duration of the work, they can get the replacement done faster and more safely. They estimate it would take a year, but were optimistic that they might be able to finish sooner.