Existing comment:
The Engine:
A two-cylinder steam engine was located on each side of the drive sheaves. Only one engine at a time was connected to the drive wheels that hauled the trains up the incline. Sylvester Welch's comment that the "engines are of the high pressure kind" refers to the fact that the steam was exhausted to the atmosphere rather than being recycled.
"The engines are of the high pressure kind; they have each two cylinders... Those for inclined planes No. 1, 3, 4, 6, 7, and 8 have cylinders of fourteen inches in diameter, and the stroke or distance which the piston moves is five feet. The number of revolutions required to produce a velocity for the ascending cars of four miles per hour, will be about fourteen, and with this number, when the engine works under a pressure of steam of about seventy pounds to the inch. The power of the larger engines, computed in the common way, would be that of about thirty-five horses."
-- Sylvester Welch, Report on the Allegheny Portage Railroad, 1833
"The engines have no fly-wheel; the second cylinder, which works a crank at right angles to the main crank, and connected with it, supplies the place of a fly-wheel in regulating the motion of the machinery. With a fly-wheel... if any derangement takes place with the rope that will cause it to stop, the machinery or the rope must break, before the fly-wheel can be stopped... Without the fly-wheel, the rope is strong enough to stop the engine without danger of being broken."
-- Sylvester Welch, Report on the Allegheny Portage Railroad, 1833 |