-33 City Hall Place.

Sub-station No. 12--108-110 East 19th Street.

Sub-station No. 13--225-227 West 53d Street.

Sub-station No. 14--264-266 West 96th Street.

Sub-station No. 15--606-608 West 143d Street.

Sub-station No. 16--73-77 West 132d Street.

Sub-station No. 17--Hillside Avenue, 301 feet West of
Eleventh Avenue.

Sub-station No. 18--South side of Fox Street (Simpson
Street), 60 feet north of Westchester Avenue.

[Illustration: SWITCH CONNECTING FEEDER TO CONTACT RAIL]

[Illustration: CONTACT RAIL JOINT WITH FISH PLATE]

The converter unit selected to receive the alternating current and
deliver direct current to the track, etc., has an output of 1,500
kilowatts with ability to carry 50 per cent. overload for three hours.
The average area of a city lot is 25 x 100 feet, and a sub-station
site comprising two adjacent lots of this approximate size permits the
installation of a maximum of eight 1,500 kilowatts converters with
necessary transformers, switchboard and other auxiliary apparatus. In
designing the sub-stations, a type of building with a central air-well
was selected. The typical organization of apparatus is illustrated in
the ground plan and vertical section on pages 101, 102 and 103 and
provides, as shown, for two lines of converters, the three
transformers which supply each converter being located between it and
the adjacent side wall. The switchboard is located at the rear of the
station. The central shaft affords excellent light and ventilation for
the operating room. The steel work of the sub-stations is designed
with a view to the addition of two storage battery floors, should it
be decided at some future time that the addition of such an auxiliary
is advisable.

[Illustration: CONTACT RAIL BANDS]

The necessary equipment of the sub-stations implies sites
approximately 50 x 100 feet in dimensions; and sub-stations Nos. 14,
15, 17, and 18 are practically all this size. Sub-stations Nos. 11 and
16 are 100 feet in length, but the lots acquired in these instances
being of unusual width, these sub-stations are approximately 60 feet
wide. Sub-station No. 12, on account of limited ground space, is but
48 feet wide and 92 feet long. In each of the sub-stations, except No.
13, foundations are provided for eight converters; sub-station No. 13
contains foundations for the ultimate installation of ten converters.

[Illustration: DIRECT CURRENT FEEDERS FROM M