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One of
three locomotives, originally equipped with hook motion valve gear and
Baldwin variable cut-off. When rebuilt as shown, Stephenson link motion
was applied.
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| 16 | M O T I V E P O W E R D E V E L O P M E N T |
| wheels 66 inches in diameter, which was completed in August, 1853. The most peculiar feature of this valve gear was the device employed for raising and lowering the sliding block on the upper arm of the rock shaft. This device consisted of a quadrant, placed so that its circumference bore nearly against a curved arm projecting downward from the sliding block, and which curved in | success of this device, his idea being that it would hold the block firmly in position on the rock shaft arm, thus preventing slip and consequent wear and lost motion. In practice it was found, however, that the straps would stretch sufficiently to allow them to buckle and break, and the chains would also stretch and frequently break altogether. Eventually, therefore, the quadrant was |
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One of
three locomotives, originally equipped with hook motion valve gear and
Baldwin variable cut-off. When rebuilt as shown, Stephenson link motion
was applied.
|
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| the reverse direction from the quadrant. Two steel straps, or chains, side by side, were interposed between the quadrant and this curved arm. One of the straps was connected to the lower end of the quadrant and the upper end of the curved arm, and the other, to the upper end of the quadrant and | entirely abandoned
and the block raised and lowered by means of a link connection.
The Baldwin variable cut-off was applied to a large number of Pennsylvania locomotives for both passenger and freight service. Among them were two fast passenger locomotives with 72-inch drivers, built late in |
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| This locomotive was originally built for the Philadelphia and Columbia R. R. and named "Corporal Trim." It was purchased by the Pennsylvania in 1857, and numbered 187. It had 16" x 22" cylinders and 54" driving wheels, and weighed 53,000 lb., with 32,200 lb. on drivers. | 
American Type Freight Locomotive, built by New Jersey Manufacturing Co., Paterson, N. J., 1856 |
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| the lower end of the curved arm. When the quadrant was rotated by means of a lever in the cab, the position of the block was shifted and the travel of the cut-off valve altered; the effect being the same as though the quadrant and arm were geared together by teeth. Mr. Baldwin was very sanguine of the | 1854 and named
"Belle' and "Flirt." The general design of these locomotives is shown in
an illustration on page 15. This design was typical of the 4-4-0 type as
built by Mr. Baldwin at that time, for both passenger and freight service.
The variable cut-off was also applied to |
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