Abernathy station (part of the Vernon East/Takoma Park map in the game) is a Metro station on the white line. It is the only route to Takoma Park.
Cave-ins throughout the Metro tunnel have flooded the floors, making it a natural habitat for mirelurks, particularly mirelurk kings. The tunnel only has one path, but it is a long one and winds around through the tunnels.
Nuka-Cola Quantum in the super mutant hideout on a shelf. (B). To get there, go down the escalator(s) and turn left twice. Go west along the Metro tracks toward what looks like a dead end. Use caution as the tracks will have frag mines along the way and then a trap (pressure plate) near the end. At the end, take a left into hideout. Inside there there you will find a Nuka-Cola vending machine and some beds.