High Quality Content by WIKIPEDIA articles! The New York, New Haven, and Harford railroad pioneered electrification of main line railroads using high-voltage, alternating current, single-phase overhead catenary. It electrified its mainline between Stamford, CT and Woodlawn, NY in 1907, and extended the electrification to New Haven, CT in 1914. While single-phase AC railroad electrification has become commonplace, the New Haven`s system was unprecedented at the time of construction. The significance of this electrification was recognized in 1982 by its designation as a National Historic Engineering Landmark by the ASME.