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of the De Glehn Compound, and Fig. 18 shows the same type of gear as applied to furnish the motion of the valves of the low-pressure cylinders. In the arrangement of the latter it is seen that the link is driven by an eccentric on the main shaft; this shaft is termed a "crank axle," because part of it is shaped to form two cranks to which the main rods of the two low-pressure cylinders (one on either side) are connected, and as the entire gear of the low-pressure, or second expansion, engine, of the cylinders and valves, both-are inside of the frame, it was clearly necessary that the eccentric should be placed on the crank axle inside the frame, with sheave and strap exactly like the Stephenson eccentric, except, of course, that but one eccentric is used for each link. Outside of the frame the return crank on the main-pin actuates the valve gear of the high-pressure engine, which is the only part that can be seen in the photoengraving Fig. 16.
At this date the most powerful passenger engine ever built is the one depicted in Fig. 19, a recent production of the American Locomotive Company for the Lake Shore & Michigan Southern Railroad, and of which some of the principal dimensions are appended; here, again, the Walschaert valve gear is in evidence; and the heaviest and most powerful switching engine in existence at this time, built for the same road by the
Fig. 19.-Prairie Type Passenger Locomotive with Walschaert Valve Gear. Built by the
21 1-2 inches
28 inches On trailing truck.
.'internal admission Total engine
79 inches Tender 158,500 pounds Total heating surface..
3,905 sq. ft.
L. S. & M.S.
44,000 pounds Valves, piston type
236,200 pounds Diameter of driving wheels, outside
Grate area. Working pressure per square inch, 200 pounds. Tender capacity, water 7,800 gallons, fuel 15 tons. Maximum
tractive power, 27,850 pounds.
55 sq. ft.
Fig. 20.—Decapod Switching Locomotive with Walschaert Valve Gear. Built by the American
Locomotive Co. The heaviest and most powerful switching engine.
270,000 pounds. Diameter of cylinder. Total engine.
270,000 pounds. Stroke of piston.
same locomotive company, is shown in Fig. 20, and also is equipped with Walschaert's motion.
In all of the illustrations of Walschaert's valve gear so far shown, as applied to American locomotives, it will have been noticed that the link is invariably suspended from a bracket that is attached to the guideyoke, and the valve-stem slide is also carried by the guides, this to insure permanency in the alignment of the gear; but with certain types of large freight engines it is sometimes inconvenient so to place the link bracket, and the American Locomotive Company have built quite a number of engines that have a very large casting extending across, under the boiler, that is really a strong cross-brace to the engine frame at the point where such a brace is most needed—an impossibility with the common link motion—and this casting is used to carry the link and reversing shaft. Some engines have this brace unattached to the guides, however, while with others it is attached rigidly to the guide-yoke, the latter type being represented in Figs. 200 and 20b, which are reproduced from the American Engineer and Railroad Journal and that journal gives the following description:
The illustrations show this new design so clearly that it needs but little explanation, and by reference to them it will be seen that the support for the small crosshead connecting to the valve-stem has been