This was a pioneering venture in mainline railroad electrification and was a proving ground for railroad electrification technology. It established single-phase alternating current as a technical and economical alternative to direct current. This concept exerted considerable influence over subsequent systems both in the United States and abroad. The major components of the system were developed by the engineering staffs of the New York, New Haven & Hartford Railroad and the Westinghouse Electric and Manufacturing Company of East Pittsburgh, Pennsylvania. 
On July 24, 1907, the first regular train to be operated under electric power completed a trip from Grand Central to New Rochelle, New York. Electrification was extended to Stamford in October of 1907. The Cos Cob plant, which switched from coal to oil and gas in the late seventies, operated until October 1986. Artifacts were given to the Smithsonian Institution.