Allentown developed quickly due to its convenient location to downtown Pittsburgh as well as due to the available transportation. Two main roads south from Pittsburgh merged on the hilltop in Allentown: Washington Road (today's Warrington Avenue) and Brownsville Turnpike Road (today's Arlington Avenue). The neighborhoods were connected at first by horse-drawn streetcars and later by the electric streetcar. In 1888 Allentown became the first site west of the Allegheny Mountains to operate an electric streetcar. Ever since then the trolley, or ‘T', has run up Warrington Avenue, Allentown's main thoroughfare, keeping hilltop residents connected to downtown Pittsburgh. Today, though, the T does not make any stops in the neighborhood, and the line (most recently known as the Port Authority's Brown Line) is used as an emergency route when the South Hills Transit Tunnel is closed. In the past, there were also five inclines that served Allentown, the most famous of which was the curved Knoxville Incline with a station at the intersection of Warrington and Arlington Avenues. Several bus routes, and many more roads connect the neighborhood with the downtown, South Side, and beyond.