The Washington Post, 8/15/17:
The Senate subway: The new epicenter of American democracy?
It’s a slightly comical transportation system in the bowels of the U.S. Capitol that few Americans know exists: the Senate subway system. Not subway like Metro — but two sets of tracks that carry underground trams ferrying lawmakers from Senate chambers to their office buildings, less than a third of a mile away.
And it’s the unlikely backdrop to the tumultuous Capitol Hill legislative goings-on of the past seven months.
The subway and its adjoining no-frills, fluorescent-lit station platform have long been a gathering place for the swarm of Capitol Hill journalists, aides and lobbyists who aim to pounce on senators as they disembark from trams or hitch a ride in the same car as a fellow lawmaker, hoping to bend an ear for the 90-second ride from one station to another.
SNIP
The tunnel to the offices first featured electric Studebaker automobiles; later, officials switched to trains on tracks out of concern that a lawmaker would one day get mowed over by a careering car.
After multiple rounds of expansions and upgrades, there are now two types of trains on the Senate side: an open-air tram to the Russell building driven by operators who ping-pong back-and-forth all day, and a Disneyland-style driverless train that runs from the Capitol to the Dirksen and Hart office buildings.
More here w/video report.