A successor company, the Boston, Hartford and Erie Railroad, completed the originally-planned Southbridge–East Thompson segment in 1867; it became the Southbridge Branch. An extension southwest from Mechanicsville to Willimantic opened in 1872. The completion of the Boston and New York Air-Line Railroad the next year created an all-rail route from New York City to Boston via Willimantic and Blackstone. The line passed to the New York and New England Railroad in 1875, the New England Railroad in 1895, and finally the NYNH&H in 1898. It was operated as part of the NYNH&H's Midland Division.[1]