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Photograph of people walking outside on a Self-Guided Tour of Capitol Hill
Visitors can tour many highlights on Capitol Hill without registering.

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The Architect of the Capitol’s challenge is unique – maintaining aging, iconic buildings; adapting state-of-the-art technology; and increasing responsiveness to environmental, security and safety considerations in a rich historical setting.
The Architect of the Capitol's challenge is unique – maintaining aging, iconic...

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The AOC Capitol Building Mason Shop successfully relocated the Magna Carta display to the Crypt.
It took both brawn and brains to move a beautiful (and hefty) treasure when the...

Architecture

Capitol Subway System

Russell Senate Office Build Subway Tunnel in 2003.
Overview 

The Architect of the Capitol (AOC) is responsible for the operation and maintenance of the Capitol "subway system." The U.S. Capitol subway consists of three lines: two on the Senate side on the north side of the Capitol, and one on the House side on the south side of the Capitol.

The purpose of the subway is to allow for safe and expedient travel for Senator and Members of Congress to travel from the office buildings to their respective chambers within the Capitol for voting.

Senate Train Early 1900s

The original subway line was built in 1909 to link the Russell Senate Office Building to the Capitol serviced by cars built by the Studebaker Company. They were first put into service on March 7, 1909, the day the Senate Subway opened. This was replaced in 1912 by a monorail vehicle which featured a wicker coach.

In 1960, an operator-controlled monorail was installed for the Dirksen Senate Office Building. A two-car subway line connecting the Rayburn House Office Building to the Capitol was built in 1965. The Dirksen monorail, which had been extended to the Hart Senate Office Building in 1982, was replaced in 1993 by an automatic train.

Last Updated: December 15, 2015