Boston opened the first subway in the United States in 1897. The initial underground section was built to relieve severe street congestion caused by horse-drawn vehicles and streetcars.
The first tunnel connected Park Street with Boylston Street and formed part of what is now the MBTA Green Line. Streetcars, rather than fully separate metro trains, originally used the tunnel.
Boston’s subway was influenced by London’s earlier underground railway, which opened in 1863. The American system developed its own combination of subway, elevated, and surface routes as the city expanded.
New York later developed a much larger subway network, but it was not the first in the United States. Chicago’s rapid-transit system also became famous for elevated tracks, while Philadelphia’s subway opened after Boston’s.