Middlesex & Boston Street Railway #323, an ACF 31-S gas bus with exit door at the Arlington Heights MTA trolley transfer station, signed up WALTHAM VIA LEXINGTON, circa 1955 The bus is parked at the sidewalk at the Arlington Heights waiting station facing Mass Ave. By this time, the carbarns had been taken down on this south side of Mass Ave. The trolley cars from Harvard square would swing around behind the bus and wait on the other side of the station for their passengers.
