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placed on an entirely separate guide, which is fastened to the back valve chamber head and through an expansion link to the guide-yoke instead of having it supported directly from the main guide, as in previous designs. The bearings for the reverse shaft and the link have been placed near together in the same casting and the radius rod of the valve gear is operated through a hanger from the arm of the reverse shaft instead of a sliding joint, as was used before when the reverse shaft was supported in a bearing on the frame between the second and third pair of drivers (as in Fig. 11). The link itself has been made somewhat larger and more bearing surface given to the block. The casting forming these bearings is fastened to a massive but not excessively heavy steel casting extending across the frame. The construction of this casting and its dimensions are clearly shown in the illustration. To this is also fastened the yoke supporting the main guides. Another change is also noticed in that the arm from the reverse shaft, to which is connected the reach rod, extends downward instead of upward. This necessitates the reach rod being placed outside the driving wheels and on an incline from the reverse lever. It is supported and steadied by a guide at the throat sheet. A change has also been made in the return-crank connection at the main-pin for the purpose of permitting it to be more quickly and easily removed,
as it has to be whenever the rods have to be taken down. While the construction at the guide yoke appears to be very heavy and cumbersome, a careful examination of the drawings will show that it is really more simple than in previous designs of this valve gear, which were more open.
The most widely different classes of service have been represented thus far in the showing of modern engines that are equipped with Walschaert's valve gear, but as a further illustration of its adaptability to various conditions without serious alteration from the simplest design, as well as to bring to notice the fact that European railways are taking advantage of the possibilities that lie in the use of this gear, Fig. 21 is presented as one of a group of thirteen engines that were exhibited at the Exposition held at Liege in 1905, by the State Railways of Belgium—the same road that graduated the inventor of the motion—and this may be said to be a lineal descendant from Walschaert's successful experimental engine of 1848. It was constructed by the Societé Anonyme la Meuse, of Schenien, from the designs of M. Flamme, General Inspector, under the direction of M. Bertrand, Director of the State Railways, and is one of a number of engines built for experimental purposes.
The plate is reproduced directly from the June, 1906, issue of the American Engineer and Railroad Journal,
and represents a 4-6-2 engine with four simple (“simple,” as the reverse of “compound,” refers to the direct use of boiler pressure in all of the cylinders of the engine: where, no matter how many cylinders there are, their pressures are exhausted after the first expansive use) cylinders arranged on a horizontal line that centres through all four pistons and the main shaft, or axle; the main rods from all of the cylinders drive on the front axle, two of the cylinders outside of the frames-one on each side of the engine-having their main rods attached to the crank-pins, while the other two cylinders inside the frame are connected with a built-up crank axle; but with reference to their points of connection on the main axle the cylinders are arranged in pairs, the outside cylinder on each side and the one next to it just inside the frame are paired, with the crank-pin and the crank axle of each pair set 180 degrees apart, or just opposite each other on the shaft. With all moving parts in the cylinders, and the main rods, being exact duplicates in the matter of weights per pair, the motion on each side of the engine is perfectly balanced. The paired cylinders on one side of the engine are connected with the main-pin and axle crank at 90 degrees from the connections of the corresponding pair of cylinders on the other side for the same reason that the two main pins of the common two-cylindered engine are always set quarter