Silver Line (Waterfront)

Silver Line (Waterfront). The Silver Line (Waterfront) is a bus rapid transit service operated by the Massachusetts Bay Transportation Authority in Boston, Massachusetts. It connects the city's downtown core at South Station with the Seaport District and Logan International Airport. The line, which opened in phases beginning in 2004, utilizes a mix of tunnel, at-grade, and elevated guideways, operating with dual-mode buses that can switch between diesel and electric trolley power.

History

Planning for improved transit to the developing South Boston Waterfront began in the 1990s, with the Massachusetts Bay Transportation Authority selecting a bus rapid transit solution. The first segment, known as the **Silver Line Waterfront Transitway**, opened in December 2004, linking South Station to the Boston Convention and Exhibition Center. This project involved constructing new tunnels under Fort Point Channel and Boston Harbor. Service was extended to Silver Line Way in 2005, and a direct connection to the terminals at Logan Airport commenced in 2006. The line's development was a key component of the Central Artery/Tunnel Project mitigation agreements and has spurred significant growth in the Seaport District.

Route and stations

The line originates at the underground bus terminal beneath South Station, where it connects with the MBTA Commuter Rail, Red Line, and Amtrak services. It travels south through the transitway tunnel, serving stations at Courthouse and World Trade Center. The route then emerges onto an at-grade, dedicated guideway, stopping at Silver Line Way before ascending onto the Ted Williams Tunnel access viaduct. It proceeds through the Massachusetts Port Authority-owned Logan Airport tunnels, serving all major terminals. Key stations provide access to landmarks like the Institute of Contemporary Art, the Boston Convention and Exhibition Center, and the Boston Fish Pier.

Service and operations

The Silver Line (Waterfront) operates two primary services: the **SL1** to Logan Airport terminals and the **SL2** to Silver Line Way. A third route, the **SL3**, previously served the Marine Industrial Park but was discontinued. Service is frequent, with headways as short as five minutes during peak periods on the core segment. Operations are integrated with the Silver Line Washington Street service at South Station, though the two lines use different vehicle technologies and operate on separate rights-of-way. The line functions as a critical transit link for airport travelers, Seaport employees, and convention attendees.

Rolling stock

The line is exclusively served by a fleet of articulated, dual-mode buses manufactured by New Flyer Industries. These vehicles, models **DE60LF** and **DE60LFR**, operate on electric trolley power within the underground transitway section to eliminate exhaust fumes. Upon exiting the tunnel at Silver Line Way, they switch to diesel power for the surface and airport segments. This specialized fleet is maintained at the Southampton Street Garage and is distinct from the standard diesel buses used on the Silver Line Washington Street.

Future plans

Long-term proposals have considered converting the Waterfront line to light rail and extending it to connect with the Red Line at Andrew or the Fairmount Line. The Massachusetts Bay Transportation Authority has also studied potential infill stations and improvements to the surface guideway. Integration with broader regional transit plans, such as those involving South Station Expansion, remains a topic of discussion. The continued development of the Seaport District and demand from Logan Airport ensure the line will be a focus of future Massachusetts Department of Transportation capital investments.

Category:Bus rapid transit in Massachusetts Category:Transportation in Boston Category:Massachusetts Bay Transportation Authority