The New York Central Railroad was forced to electrify its lines into Manhattan as a result of a horrific wreck in the Park Avenue Tunnel in 1902 caused by smoke from steam locomotives. The present Grand Central Terminal, along with its very extensive electrified underground rail yards, formally opened in 1913.
This electrification used conventional 600 volt D.C. third rail technology and the equipment was supplied primarily by the General Electric Company. The power supply to several rotary converter substations located along the line was 11,000 volt, three-phase, 25-cycle alternating current that was generated at two power houses.
The first was “Port Morris”, named for the section of The Bronx in which it was located, and the second was “Glenwood”, again named for the section of the City of Yonkers (north of New York City) in which it was located. The Port Morris station was on the East River, between Hell Gate and Rikers Island. The Glenwood station still stands on the east bank of the Hudson River. Port Morris station was completed in 1906 and Glenwood in 1907. The designs of the two steam generating stations were virtually identical.
Rotary substation No. 1 supplied the third rail in the Park Avenue Tunnel into Grand Central Terminal, as well as the Grand Central yards. Originally, it was located at Park Avenue and 50th Street along with a steam plant that supplied steam for heating Grand Central. During the 1930’s, however, this facility was demolished for the construction of the present Waldorf-Astoria Hotel. The rotary substation was moved to a location beneath Grand Central Terminal itself, where it remains today (now using solid-state rectifiers instead of rotary converters).
Substation No. 2 was located at Mott Haven in The Bronx which was the junction point for the “Hudson” and “Harlem” divisions of the railroad. Substations No. 3 through No. 6 were along the Hudson Division, with No.4 being at Glenwood Station. Substations No. 7 through No. 9 were along the Harlem Division.
Initially, the Port Morris and Glenwood stations each contained four General Electric 5000 kilowatt steam turbine driven generators. By 1929, an additional 20,000 kilowatt turbine unit had been installed at Port Morris and two of the original 5000 kilowatt units at Glenwood had been replaced by three 20,000 kilowatt turbine units.
In 1927, the operation of both stations had been taken over by the New York Edison Company (the predecessor of Consolidated Edison).
The stations continued to be operated by Consolidated Edison, but Port Morris was retired in 1952 and had been demolished by the late 1980’s. A power system switching house still stands at that location, however.
The Glenwood Station was retired in the early 1960’s. The derelict structure still stands today and plans have been proposed for decades for its adaptive re-use. As late as the year 2011, its original two smokestacks were still standing !
The rotary converter substations along the Hudson and Harlem lines (now part of the Metro-North Railroad) have all been replaced in function by new solid-state rectifier substations. Some of the old substation buildings still stand, now derelict. The last functioning rotary converter substation (using 25-cycle power) was the Marble Hill Substation in The Bronx which was retired in May of 1989.