When the railroads serving Boston were first laid out and built, each one stopped at its own terminal. The four terminals serving the south-side railroads were as follows:

• The New York and New England Railroad crossed the Fort Point Channel from South Boston, just south of the present Summer Street Bridge, and terminated just east of Dewey Square (right at the north end of today's South Station).
• The Old Colony Railroad had a long passenger terminal on the east side of South Street, stretching from Kneeland Street south to Harvard Street. This site is now part of the South Bay Interchange, near the South Station bus terminal.
• The Boston and Albany Railroad's passenger terminal was in the block bounded by Kneeland Street, Beach Street, Albany Street (now Surface Artery) and Lincoln Street. This later became a freight house, and is now a block in Chinatown; the passenger terminal was moved to the west side of Utica Street, from Kneeland Street south to a bit past Harvard Street, now part of the South Bay Interchange.
• The Boston and Providence Railroad continued straight where it now merges with the Boston and Albany, terminating at Park Square, with the passenger terminal on the south side of Providence Street from Columbus Avenue west about 2/3 of the way to Berkeley Street.

South Station combined the four terminals in one spot (a union station.)

Opening

A view of the Atlantic Avenue Elevated in front of South Station; the elevated station was at far right

South Station opened as South Union Station on January 1, 1899 at a cost of $3.6 million (1899 dollars). It became the busiest station in the country by 1910. A station on the Atlantic Avenue Elevated served the station from 1901 to 1938; what is now the Red Line subway was extended from Park Street to South Station in 1913. The train shed was replaced in a 1930 renovation. While the station handled 125,000 passengers each day during World War II, after the war passenger rail declined in the U.S. In 1959, the Old Colony Railroad, which served the South Shore and Cape Cod, stopped passenger service. The New Haven Railroad went bankrupt in 1961. South Station was sold to the Boston Redevelopment Authority (BRA) in 1965. Portions of the station were demolished and the land was used to build the Boston South Postal Annex and the Stone and Webster building.

Looking north at the merge of the two approaches, with the two pairs of tracks approaching the lower-level loop at right; the terminal is in the background

The never-used lower-level loop platforms

In the original configuration, two tracks came off each approach to join into a four-track line and then run under the main platforms in a two-track loop. These tracks were never put into service, and later became a parking lot and bowling alley for employees.[1]

Renovation

In 1978, the BRA sold what was left of the station, now on the National Register of Historic Places, to the MBTA, though the BRA retained air rights over the station. Funding was obtained for a major renovation of the station that was completed in 1989. A total of 13 tracks became available, all with high level platforms and some capable of handling 12 car trains. Piers were installed for the eventual construction of an office building and bus station above the tracks. After some delays, an inter-city bus terminal opened in October 1995, replacing one on top of the I-93 Dewey Square Tunnel diagonally across from the station between Summer Street and Congress Street. The new bus terminal has been called “the best bus facility in the country”^{[citation needed]} and has direct ramp connections to I-93 and the Massachusetts Turnpike. The renovations, including the bus terminal, cost $195 million (2001 dollars).

The Red Line subway platforms were extended to allow 6 car trains in 1985 and renovated again in 2005, as part of the Silver Line Phase 2 project.

Future

Planned system improvements should result in additional passenger traffic. Construction is underway on a commuter rail line to Greenbush that would terminate at South Station. Silver Line Phase 3 would build a tunnel connecting South Station with the Silver Line Phase I BRT service to Dudley Square, Roxbury. Current plans also include commuter rail service to T.F. Green Airport in Rhode Island and, possibly, to Fall River and New Bedford, Massachusetts.

Proposed South Station Tower

Plans are progressing to construct a 40-story mixed-use (office, hotel and residential) tower above the track platforms, starting in 2007. The tower proposal includes privately-funded improvement to the terminal that would increase the number of bus berths and provide a direct interior connection between the subway entrance area and the bus terminal. A relocation of the adjacent Boston South Postal Annex might allow additional expansion.