. Bulletin. Science. A—Truck frdoie B—Equalizing lever C—Locomotive frame D—Double incline plane (Centering derize) E—Truck bolster F—Swivel pin Dnwn byT. H. White. Tunc. IJfiO Figure 3.—Typical 4-\vheel Bissell Safety truck of i860. This drawing is based on plate 69 of Alexander L. HoUey's, American and European Railway Practice in the Economical Generation of Steam, New York, 1861. (Smithsonian photo 46g.^6) For single axle engines this simple form of truck was entirely satisfactory, but it proved less satisfactory for 4- and 6-coupled machines. Also, as train speeds increased, so did the nu
. Bulletin. Science. A—Truck frdoie B—Equalizing lever C—Locomotive frame D—Double incline plane (Centering derize) E—Truck bolster F—Swivel pin Dnwn byT. H. White. Tunc. IJfiO Figure 3.—Typical 4-\vheel Bissell Safety truck of i860. This drawing is based on plate 69 of Alexander L. HoUey's, American and European Railway Practice in the Economical Generation of Steam, New York, 1861. (Smithsonian photo 46g.^6) For single axle engines this simple form of truck was entirely satisfactory, but it proved less satisfactory for 4- and 6-coupled machines. Also, as train speeds increased, so did the number of derailments. Many of these could be traced to the inability of the engine to negotiate curves at speed. Levi Bissell, a New York inventor who investigated this problem in the 1850's, correctly analyzed the difficulty. He ob- served that when the engine was proceeding on straight tracks the leading truck tended to oscillate and chatter about the center pin, and he noted that it was this action that imparted a fearful pitching motion to the locomotive at speed. The derailments were traced to the action of the truck as the engine entered a curve. This action can be more easily understood from reference to Bissell's patent drawing in figure 2. For example, let us say that an 8-wheel engine, fitted with a center-swing truck, enters a right-hand curve. The left truck wheels bear hard against the left rail. The drivers jam obliquely across the track, with the right front and left rear wheels grinding into the rails. As a result, the locomotive tends to leave the track in the direction of the arrow shown on the figure (bottom drawing). It will be noted that the truck center pintle is in fact the fulcrum for this leverage. Under such strain the truck wheels are particularly likely to leave the rails when they encounter an obstruction. Once derailed, the truck would then spin around on the deadly center pin, throwing the locomotive over. In effect, then, the center
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Keywords: ., bookauthorunitedstatesdepto, bookcentury1900, booksubjectscience
