Former bus garages
Boston Elevated Railway/MTA/MBTA
Eagle St was a former trackless trolley garage until 1962, when service was converted to bus for services in East Boston, Revere, and Chelsea. Eagle St operated Routes 110-121 until 1981, when the garage closed. The routes were split between Charlestown (routes 110-112) and Lynn (114-121) garages.
For a while, the Clarendon Street carhouse/trackless trolley barn served some of the Charlestown-Arlington routes until they were taken over by the Charlestown garage.
Park St Dorchester
All trackless trolley routes that operated in Dorchester operated out of Park St. until 1958. Most of the routes now operate out of the Cabot garage, except for Route 20, which operates out of Quincy garage. For a short history of the routes and some pictures, click this link: Dorchester Trackless Trolley Routes
Until 1985, Bennett St, near the former Red Line near Eliot Square, had its own bus operations and garage. When the Red Line extension to Alewife opened, all of the bus routes operating for the Cambridge area operated out of the Charlestown garage. (The trackless trolleys already had a facility in North Cambridge, but from 1981-1985 the trackless trolleys did not run through the Harvard tunnel, but around Cambridge Common.)
Bartlett Street had operated with streetcars since the BERy days in the 1890s before converting to diesel buses in the 1940s. Bartlett Street garage was considered a separate garage, operating such routes as the Harvard-Dudley via Allston and Harvard-Dudley via Mass Avenue; but sometimes, Bartlett was used as a satellite and repair garage for the Arborway garage. When the Arborway garage closed in 1985, Bartlett assumed all of Arborway's operations, including bus storage and repair duties. This lasted over 18 years until the resumption of all operations to the Arborway garage on December 27, 2003, which now operates with mainly CNG buses.
Tewksbury garage served the Lowell routes (700 series routes) until the inception of the Lowell Regional Transit Authority in late 1970s. Click the following link to view a history compiled from Bob Hussey: LRTA History
Brockton division routes were numbered in the 600 series when they were first acquired from Eastern Mass in 1968, but in 1972, the Union Street Railway took over the routes. In 1976, USR left Brockton Area Transit operates all service in Brockton, Stoughton and Easton.
Middlesex and Boston
Before 1972, the Middlesex & Boston Street Railway operated buses within Waltham, Newton and Lexington. They most likely had a garage in Newton or Waltham, operating Old Look and occasionally New Look buses. When the routes were acquired by the MBTA, they were assigned routes in the 500 series until 1982, when they used route numbers formerly used by other bus routes in the 52-76 series. In 1996, the 300 series express buses and routes 53, 54, 56 and 58 were renumbered into Routes 500-505, 553, 554, 556 and 558.