From historical photoblog Shorpy we get this underground gem:
That’s the Senate Subway, c. 1915, just two years after it started operation, part of the whole Capitol Subway System. After the jump, you can see how the
Senate Subway still uses open-air cars, though somewhat more modernized.
(Update: Well, boy is my face red; the ‘today’ photo after the jump is actually from the House subway, not Senate. You can tell I’ve never ridden either system, not having had the privilege of working on the Hill myself.)
(Thanks to Linda for the photo.)