In the middle just above the second floor windows you can read Manhattan Railway Co. / Station 7. (Click for closer view.)
According to the new building notices at metrohistory.com plans were filed in 1900 for 1782 3rd Avenue on the southwest corner of 99th St. at an estimated cost of $28,000 as a 4-story brick storage house (NB 791-00). Owner and architect were given as Manhattan Railway Co.
The wikipedia article on the Manhattan Railway Company includes, "The Manhattan Railway Company was an elevated railway company in Manhattan and the Bronx, New York City, United States. It operated four lines: Second Avenue Line, Third Avenue Line, Sixth Avenue Line, Ninth Avenue Line ... Substation 7, built by the company around 1898 to convert AC to DC, survives at 1782 Third Avenue, at 99th Street and is on the National Register of Historic Places." Also, "Substation 7 is a traction substation located at 1782 Third Avenue at 99th Street on the Upper East Side of Manhattan. The Manhattan Railway Company built it in order to electrify the Second, Third and Ninth Avenue elevated lines. It served as a power source for the IRT Lexington Avenue Line from 1918 until the 1970s." (Substation 7)
The website http://www.midcontinent.org/ gives the following timeline:
|New York Elevated Railroad Co organized 27 Oct 1872|
|Gilbert Elevated Co chartered 12 June 1872|
|Manhattan Elevated Co organized 1873|
|1878 NYERR constructed Third Ave line from battery to 129th St|
|20 May 1879 NYERR & Gilbert (now Metropolitan) lines leased to Manhattan Co.|
|1884 Jay Gould gained control of Manhattan Co|
|1886 Gould gained ownership of Metropolitan Elevated Railroad & New York Elevated Railroad|
|1891 Jay Gould died / his son George Jay Gould became president of Manhattan Railway Co|
|1 April 1903 entire Manhattan Elevated system leased to the Interborough Rapid Transit Co (IRT)|
http://www.nycsubway.org/ adds the following about New York's elevated lines, "There were four elevated roads -- the Sixth Avenue, Ninth Avenue, Third Avenue, and Second Avenue -- in Manhattan, all completed by the early 1880's and run by the Manhattan Elevated Railroad Company, which, after 1884, was wholly controlled by Jay Gould and Russell Sage."
Copyright © 2016 Walter Grutchfield