Senators began using cars on the underground tunnels to commute from their office buildings to the US Capitol as soon as the offices were built.

The Russell Senate Office Building, the oldest congressional office in the nation's capital, opened its doors to senators in 1909, and as soon as they began operating in the offices, Studebaker Company cars were commissioned to move the legislators on a subway line between the office building and the Capitol building, per the Architect of the Capitol.

Only three years later, the cars were replaced by an electric monorail with wicker seats that could carry more passengers at once and made the trip faster and more efficient.

The original Senate subway became a necessity whenever the Senate was in session, making 225 trips daily and whisking senators from their offices to the Senate floor during votes.

Senators had the front seats of each car reserved for them at all times, and could summon the monorail by ringing a bell three times, Untapped reported.

The monorail quietly kept pace with history, carrying lawmakers amid historic moments, such as the election of the first female senator, Hattie Caraway, who is pictured riding one of the cars in 1937.

By 1960, a second monorail was built to accommodate the expansion of the Capitol offices with the construction of the Dirksen Senate Office Building, which was finished in 1958.

Another subway line connecting the Capitol to the newly built Rayburn House Office Building began service in 1965, and in 1982, the Dirksen line was extended to the Hart Senate Office Building, which was finished that year.

By the late 1980s, lawmakers had begun stressing the need for a more efficient subway system, which became more apparent as lawmakers showed up late or even missed votes on the floor due to long wait times.

A modernized, magnet-powered subway was built in 1994, inspired by the railways in Walt Disney World in Orlando, Florida, per the US Senate website.

Today, the same automated line continues moving senators between their offices and the Capitol.

The subway connecting the Dirksen and Hart office buildings with the Capitol is used by lawmakers daily to make the two-minute journey.

However, the time it saves compared to walking the tunnels is only 90 seconds each way for Senators in the further office buildings and even shorter for those in the closer one, the Washington Examiner reported.

With the time saved being so minimal, lawmakers often choose to walk in the subway-adjacent walkway instead. Sometimes, they will invite journalists to walk with them.

The train line connecting the Russell building to the Capitol features a different type of car, more similar to its historic iterations.

The manually controlled open-air tram has two cars that travel to and from the oldest Senate office building on request.

Although smaller and older, the Russell line has fewer malfunctions than its fully automated counterpart.

Although convenient in some ways, the Capitol subway covers a small area, and travels at relatively slow speeds.

The line connecting the Capitol with the Russell building only spans about 1,000 feet and its manually operated cars run at an average speed of 18 mph.

Entry points on the Dirksen automated monorail have platform doors such as the ones you would see in an airport rail line or in some countries' subway systems.

While the system isn't open to the public unless you're a member of Congress, a credentialed press member, or a staffer on Capitol Hill, lawmakers and their teams can offer tours of the trains to their constituents.

The Rayburn line is the only one in the subway system to have a "members only" car, which can be used solely by members of Congress. The rest of the subway cars can be used by anyone with an invitation.

If you decide to pay a visit — and get a Congress staff member to give you a tour — you could be sitting in a car next to a future US president.

A senator's commute from their office to the Capitol can often serve as an informal briefing time with their staff.

Photos show senators using the private cabin to catch up on phone calls.

Other senators might use the time to read up on policy proposals and relevant information of the day.

Other senators simply prefer to be left alone during their short ride, giving them time to contemplate the day or just take a break.

On the Capitol side, journalists often crowd the small area between the subway exit and the Senate floor to ask lawmakers questions.

Although they have a private subway system to go between their offices and the Capitol building, lawmakers sometimes have to rush to catch their train and avoid longer waits.

The automated Dirksen monorail often has longer wait times than its older open air counterpart.

Legislators often have to wait a few minutes at the terminal for the next train car to arrive to go back to their offices or to make it to the Senate floor.

Senators can often face stoppages in the Capitol subway, which often malfunction and stop along their journey.

For some, the gamble of taking the subway isn't worth the minimal time it saves.

In July 2025, the Washington Examiner reported that the subway system "keeps trapping US senators," due to the frequent malfunctions, which have led some legislators to call for increased funding.

West Virginia Republican Senator Jim Justice is known to bring his English bulldog, Babydog, along with him to his office in the Hart Senate Office Building, where Babydog recently had her sixth birthday party amid the ongoing government shutdown.