During the trusteeship, the lease of the eastern Connecticut lines to the Shore Line Electric Railway was terminated on April 1, 1920. Just prior to the return to New Haven control, in early November 1925, the state authorized the system's first major abandonment and replacement with intercity buses, on the portion of this division north of Norwich. Abandonments progressed steadily through the 1920s and 1930s, with only city and suburban lines remaining after 1937. The Hartford Division was completely converted to buses on July 26, 1941, but trolleys continued to run on the streets of New Haven until September 25, 1948. The delay in conversion caused by World War II allowed the Branford Electric Railway Association to acquire, in 1947, a portion of the New Haven-Branford line that had been built on private right-of-way and create the Shore Line Trolley Museum.