Red Line trains will single track in two work zones this weekend, starting at 10 p.m. on Friday, Feb. 22, and continuing through closing on Sunday.

Trains will single track between Friendship Heights and Van Ness "to allow for track, fastener and insulator renewal," and between Takoma and Rhode Island Avenue "to allow for platform reconstruction and rail joint elimination for a smoother ride," Metro reported on its website.

During the weekend, trains between Shady Grove and Glenmont will operate every 24 minutes in each direction. On Saturday and Sunday, between 9 a.m. and 9 p.m., extra trains will be added between Van Ness and NoMa-Gallaudet, so that trains will run about every 12 minutes between those stations, Metro added.

Metro advised passengers traveling through either work zone to allow about 20 minutes of extra travel time.

Read more about this weekend's scheduled track work at Metro's website.