Metro has announced station closures and train detours for Columbus Day weekend (which extends through Monday, a federal holiday that not everyone gets to take off) while they replace large pieces of track and inspect and maintain others. They provide a tiny and poorly-compressed map of the closures that might be helpful if you’re willing to squint and compare it to the regular map. (Metro! I do this for a living! Help me help you!)
The short version is, the Yellow and Green lines will be a nightmare, and you should avoid them if you need to take them through the eastern part of the city.
The two ends of the Green line will be operating, but the segment in the middle, between Navy Yard and Gallery Place/Chinatown, will not operate AT ALL. So if you’re someone dependent on the Green Line to get into the city from the Branch Avenue end… you’re screwed, because there are no transfer stations along any part of that segment. If you’re using the other end of the Green Line, you’ll still be able to switch lines at Gallery Place to get around.
Since the Yellow Line’s bridge over the Potomac is part of theInstead of heading toward Fort Totten from L’Enfant, the Yellow Line will basically be doubling a portion of the Blue Line route until Stadium/Armory instead of coming over the river from the Pentagon, and will come into L’Enfant on the lower platform with the Blue/Orange lines. So you’ll still be able to get around if you’re dependent on the Yellow Line, but with some hopping around and transferring multiple times if you want to get to Fort Totten.