Manhattan.  Rapid Transit.

Diameter of high-pressure cylinders, inches, 44 42
Diameter of low-pressure cylinders, inches, 88 86
Stroke, inches, 60 60
Speed, revolutions per minute, 75 75
Steam pressure at throttle, pounds, 150 175
Indicated horse power at best efficiency, 7,500 7,500
Diameter of low-pressure piston rods, inches, 8 10
Diameter of high-pressure piston rods, inches, 8 10
Diameter of crank pin, inches, 18 20
Length of crank pin, inches, 18 18

Double Ported   Single Ported
Type of Low-Pressure Valves.                    Corliss         Corliss
Type of High-Pressure Valves.                   Corliss       Poppet Type

Diameter of shaft in journals, inches, 34 34
Length of journals, inches, 60 60
Diameter of shaft in hub of revolving
  element, inches 37-1/16 37-1/16

The guarantees under which the main engines are being furnished, and which will govern their acceptance by the purchaser, are in substance as follows:  First.  The engine will be capable of operating continuously when indicating 11,000 horse power with 175 lbs. of steam pressure, a speed of 75 revolutions and a 26-inch vacuum without normal wear, jar, noise, or other objectionable results.  Second.  It will be suitably proportioned to withstand in a serviceable manner all sudden fluctuations of load as are usual and incidental to the generation of electrical energy for railway purposes.  Third.  It will be capable of operating with an atmospheric exhaust with two pounds back pressure at the low pressure cylinders, and when so operating, will fulfill all the operating requirements, except as to economy and capacity.  Fourth.  It will be proportioned so that when occasion shall require it can be operated with a steam pressure at the throttles of 200 pounds above atmospheric pressure under the before mentioned conditions of the speed and vacuum.  Fifth.  It will be proportioned so that it can be operated with steam pressure at the throttle of 200 pounds above atmospheric pressure under the before mentioned condition as to speed when exhausting in the atmosphere.  Sixth.  The engine will operate successfully with a steam pressure at the throttle of 175 pounds above atmosphere, should the temperature of the steam be maintained at the throttle at from 450 to 500 degrees Fahr.  Seventh.  It will not require more than 12-1/4 pounds of dry steam per indicated horse power per hour, when indicating 7,500 horse power at 75 revolutions per minute, when the vacuum of 26 inches at the low pressure cylinders, with a steam pressure at the throttle of 175 pounds and with saturated steam at the normal temperature due to its pressure.  The guarantee includes all of the steam used by the engine or by the jackets or reheater.