commuter rail service to waltham station has remained relatively constant since the mbta was formed in 1964. however, several nearby stops on the fitchburg line and the central mass branch were closed in the early years of the mbta. the former depot building, which included a large clocktower, was demolished in 1962. the waltham interlocking tower is located next to elm street; it controlled the junction with the watertown branch railroad, which operated passenger service until july 9, 1938.