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The New York Subway: Chapter 07, Lighting System for Passenger Stations and Tunnel

From nycsubway.org

In the initial preparation of plans, and more than a year before the accident which occurred in the subway system of Paris in August, 1903, the engineers of the Interborough Company realized the importance of maintaining lights in the subway independent of any temporary interruption of the power used for lighting the cars, and, in preparing their plans, they provided for lighting the subway throughout its length from a source independent of the main power supply. For this purpose three 1,250-kilowatt alternators direct-driven by steam turbines are installed in the power house, from which point a system of primary cables, transformers and secondary conductors convey current to the incandescent lamps used solely to light the subway. The alternators are of the three-phase type, making 1,200 revolutions per minute and delivering current at a frequency of 60 cycles per second at a potential of 11,000 volts. In the boiler plant and system of steam piping installed in connection with these turbine-driven units, provision is made for separation of the steam supply from the general supply for the 5,000 kilowatt units and for furnishing the steam for the turbine units through either of two alternative lines of pipe.

The 11,000 volt primary current is conveyed through paper insulated lead-sheathed cables to transformers, located in fireproof compartments adjacent to the platforms of the passenger stations. These transformers deliver current to two separate systems of secondary wiring, one of which is supplied at a potential of 120 volts and the other at 600 volts.

The general lighting of the passenger station platforms is effected by incandescent lamps supplied from. the 120 volt secondary wiring circuits, while the lighting of the subway sections between adjacent stations is accomplished by incandescent lamps connected in series groups of five each and connected to the 600 volt lighting circuits. Recognizing the fact that in view of the precautions taken it is probable that interruptions of the alternating current lighting service will be infrequent, the possibility of such interruption is nevertheless provided for by installing upon the stairways leading to passenger station platforms, at the ticket booths and over the tracks in front of the platforms, a number of lamps which are connected to the contact rail circuit. This will provide light sufficient to enable passengers to see stairways and the edges of the station platforms in case of temporary failure of the general lighting system.

The general illumination of the passenger stations is effected by means of 32 C. p. incandescent lamps, placed in recessed domes in the ceiling. These are reinforced by 14 C. p. and 32 C. p. lamps, carried by brackets of ornate design where the construction of the station does not conveniently permit the use of ceiling lights. The lamps are enclosed in sand-blasted glass globes, and excellent distribution is secured by the use of reflectors.

The illustration on page 122 is produced from a photograph of the interior of one of the transformer cupboards and shows the transformer in place with the end bell of the high potential cable and the primary switchboard containing switches and enclosed fuses. The illustration on page 123 shows one of the secondary distributing switchboards which are located immediately behind the ticket booths, where they are under the control of the ticket seller.

In lighting the subway between passenger stations, it is desirable, on the one hand, to provide sufficient light for track inspection and to permit employees passing along the subway to see their way clearly and avoid obstructions; but, on the other hand, the lighting must not be so brilliant as to interfere with easy sight and recognition of the red, yellow, and green signal lamps of the block signal system. It is necessary also that the lights for general illumination be so placed that their rays shall not fall directly upon the eyes of approaching motormen at the head of trains nor annoy passengers who may be reading their papers inside the cars. The conditions imposed by these considerations are met in the four-track sections of the subway by placing a row of incandescent lamps between the north-bound local and express tracks and a similar row between the southbound local and express tracks. The lamps are carried upon brackets supported upon the iron columns of the subway structure, successive lamps in each row being 60 feet apart. They are located a few inches above the tops of the car windows and with reference to the direction of approaching trains the lamps in each row are carried upon the far side of the iron columns, by which expedient the eyes of the approaching motormen are sufficiently protected against their direct rays.

Lighting of the Power House

For the general illumination of the engine room, clusters of Nernst lamps are supported from the roof trusses and a row of single lamps of the same type is carried on the lower gallery about 25 feet from the floor. This is the first power house in America to be illuminated by these lamps. The quality of the light is unsurpassed and the general effect of the illumination most satisfactory and agreeable to the eye. In addition to the Nernst lamps, 16 C. p. incandescent lamps are placed upon the engines and along the galleries in places not conveniently reached by the general illumination. The basement also is lighted by incandescent lamps.

For the boiler room, a row of Nernst lamps in front of the batteries of boilers is provided, and, in addition to these, incandescent lamps are used in the passageways around the boilers, at gauges and at water columns. The basement of the boiler room, the pump room, the economizer floor, coal bunkers, and coal conveyers are lighted by incandescent lamps, while arc lamps are used around the coal tower and dock. The lights on the engines and those at gauge glasses and water columns and at the pumps are supplied by direct current from the 250 volt circuits. All other incandescent lamps and the Nernst lamps are supplied through transformers from the 60 cycle lighting system.

Emergency Signal System and Provision for Cutting Off Power from Contact Rail

In the booth of each ticket seller and at every manhole along the west side of the subway and its branches is placed a glass-covered box of the kind generally used in large American cities for fire alarm purposes. In case of accident in the subway which may render it desirable to cut off power from the contact rails, this result can be accomplished by breaking the glass front of the emergency box and pulling the hook provided. Special emergency circuits are so arranged that pulling the hook will instantly open all the circuit breakers at adjacent sub-stations through which the contact rails in the section affected receive their supply of power. It will also instantly report the location of the trouble, annunciator gongs being located in the sub-stations from which power is supplied to the section, in the train dispatchers' offices and in the office of the General Superintendent, instantly intimating the number of the box which has been pulled. Automatic recording devices in train dispatchers' offices and in the office of the General Superintendent also note the number of the box pulled. The photograph on page 120 shows a typical fire alarm box.

Image 17588
(31k, 263x478)
Photo by: IRT Company
Location: Interborough Subway

Image 17591
(30k, 340x469)
Photo by: IRT Company
Location: Interborough Subway

Image 17592
(41k, 349x478)
Photo by: IRT Company
Location: Interborough Subway

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