FYI
Otis Evevator has supplied and installed single flight escalators 100 feet in length.
The longest multiflight system was 700 feet long and was outdoors.
My guess would be Rosslyn. That was my first thought at reading the OP.
For a poor-depth-perceptioned/fearful of heights person who’s often thought of using the Metro in DC but never has for this very reason, can anyone confirm the existence of elevators in the stations?
If it’s anything like the London Underground, they’re only used for stations which are too deep for escalators to be practical. They’re avoided otherwise, because they can’t cope with the capacity that escalators can. And it’s rare to find a combination of the two, because you’d have to either build a long horizontal tunnel at the bottom so the lift shaft emerges at the top alongside the escalator, or have two surface entrances 100m apart. (In the 1930s, many London stations were rebuilt with escalators, meaning the old surface entrance was abandoned and another built some way away.)
The one at Moszkva Ter in Budapest, Hungary is amazingly long, too. I think it’s 1 minute 50 from top to bottom, but escalators there are quite faster than the ones in the US. I’ll be there next week, so I’ll see if I can figure out how long it is.
Some stations have elevators. Bethesda does for example.
All underground metro stations have elevators, after Metro was sued by handicapped rights groups some years back. Although it’s a crap shoot whether an elevator will be in working order on any given day.
All Metro stations are required to have elevator access between the street, mezzanine, and/or train levels if they are multi-level.
If a station’s elevators cannot provide complete train-to-street access, they announce this and suggest you ride to an adjacent station and take a free shuttlebus back to the station you wanted.
Now, if you’re claustrophobic, the elevators may present another problem. All of them that I’ve ever ridden in are clear-walled, and the feeling I get when descending from street level and seeing the ground “swallow me up” must only be worse with claustrophobia.