Metro riders should expect delays on the Blue and Orange lines this weekend due to maintenance work.

The Blue Line will single track between Arlington Cemetery and Foggy Bottom to allow for fiber-optic cable installation. Orange Line trains will single track between Clarendon and Foggy Bottom, also to allow for fiber-optic cable installation.

Trains on both lines will run every 26 minutes between 10:00 tonight (Friday) and system closing on Sunday.

Delays due to maintenance work are also expected on the Red and Green lines. Metro says the work is part of its larger infrastructure “rebuilding” effort.

“Metro is investing $5.5 billion to install new rail, ties, platforms, escalators, signals, lighting, communication systems, and more,” the agency said in a press release. “It represents the largest capital investment — and work effort — since the system’s original construction in the early 1970s.”