The Silver Line is the MBTA's umbrella name for Bus Rapid Transit. It consists of two separate divisions and routes: Silver Line Washington Street (SL4 and SL5) began in 2002 using standard articulated CNG buses in bus lanes between Dudley Square and downtown (SL4 is a loop around via Downtown Crossing), charging bus fares with standard on-board fare collection (not on street like New York City's Select Bus Service), and stops that do have slightly larger shelters and Fare Vending Machines. SL5 is a branch to a surface stop at South Station that began in 2009. The infrastructure for this type of bus based system is not substantial enough for me to include on this website.
The Silver Line Waterfont is though a real bus rapid transit line that uses dual-mode buses and charges subway fares. It begins underground at South Station within fare control and runs under trolley wire stopping at two intermediate stations underground (each with faregates having passengers pay before they board the bus) before running to the surface at Silver Line Way, dropping its trolleybus poles and running on its own power for the rest of its way to Logan Airport (SL1) or Design Center (SL2). In 2018 SL3 entered operations that includes a surface transitway on former railroad line through Chelsea that I hope to someday photograph. The four station of this true transitway with underground stations that I have photographed and included on this website and are more worthy than quite a few of the Geen Line stations included that I have also included.

Waterfront Transitway Stations Buses Continue on street to Logan Airport (SL1), Design Center (SL2), or Chelsea (SL3)