WASHINGTON — Metro will start track work early on Monday and Tuesday evenings to replace nearly 400 feet of rail along a sharp curve where a train derailed last summer.

The track work begins at 8 p.m. Monday, Feb. 22 and Tuesday, Feb. 23 and will include work on third-rail insulators and the fasteners that hold the rails in place near the Smithsonian Station.

Orange and Blue line trains will use a single track to pass through the area between Smithsonian and Federal Center SW. Silver Line trains will run between Ballston and Wiehle-Reston East.

Fasteners need to be replaced throughout the system and were partly linked to rails that had spread too far apart, but missed by Metro track inspectors, and led to an empty train derailing outside the Smithsonian Station in August.

Metro says the repairs are not related to the derailment.

The derailment led to the resignation of Metro’s chief safety officer after it emerged that a track inspection vehicle had detected the dangerous track conditions weeks earlier, but that warning had been deleted and the track was never repaired.

Walking track inspectors had also missed the issue.

The Federal Transit Administration has directed Metro to increase walking track inspection resources.