Metro says five of its six rail lines will be affected by weekend work.
Metro has closed two red line stations in Maryland after smoke was reported in a tunnel.
Metro says the red, orange and blue lines will be affected by work this weekend.
Metro says weekend work will only affect the red line over the Independence Day holiday weekend.
Passengers traveling on the orange, blue, and green lines will have to wait longer for Metro trains this weekend.
Metro plans to close five stations on the red line for weekend work.