Unlike the main line, the Winthrop Loop was not paralleled by mainline railroads or Boston Elevated Railway (BERy) streetcar lines. The town of Winthrop rejected plans for BERy to provide bus service. Instead, Saugus Transit began operating Winthrop Beach - bus service as soon as the BRB&L was abandoned; it was granted a permanent operating certificate under the name Rapid Transit Inc in March. The two routes split at Winthrop Beach and roughly paralleled the two halves of the Loop; a connecting service also operated through to Point Shirley.
