I- 



--Jt 



Figure 7. — Bissell's 2-\vheel truck of 1858 as shown by the drawing for British patent 2751, issued December i, 



were cheaper and simpler to construct, and not, as 

 has been claimed, that the V's wore out quickly." 



Smith's swing-bolster truck, with the heart pendant 

 link, a later refinement, became the dominating form 

 of centering devices and was used well into this cen- 

 tury. It was to be superseded in more recent years 

 by the constant resistance and gear roller centering 

 devices which, like Bissell's invention, depended on the 

 double incline plane principle. 



The British-born engineer William S. Hudson, 

 superintendent of the Rogers Works and an early 

 proponent of the Bissell truck, in 1864 obtained a 



patent '"' for improving Bissell's safety truck. Hudson 

 contended that since the Bissell arrangement had 

 a fixed pivot point it could traverse only one given 

 radius accurately. He proposed to replace the fixed 

 pivot with a radius bar (see fig. 5) one end of which 

 was attached to the locomotive under the smoke-box 

 and the other to rear of the truck frame, at the same 

 point of attachment as in the Bissell plan. Thus, 

 according to Hudson, the pivot point could move 

 laterally so that the truck might more easily accom- 

 modate itself to a curve of any radius. He further 

 claimed that a better distribution of weight was 

 efTected and that the use of the radius bar relieved 

 the center bearing casting of much of the strain of 

 propelling the truck. 



" Gustavus Weissenborn in his authoiitative American Loco- 

 motive Engineering and Railway Mechanism (New York, 1871, 



p. 131), stated that when in use the V's soon acquired a polished 



surface which seemed to defy wear. " U.S. patent 42662, May 10, 1864. 



PAPER 24: INTRODUCTION OF THE LOCOMOTIVE SAFETY TRUCK 



125 



