Figure i. — Design drawing showing the 4-wheel leading truck, developed in 1831 by John B. Jervis, applied 

 to the Brother Jonathan. This locomotive, one of the earliest to use a leading truck, was built in June 1832 

 by the West Point Foundry Association for the Mohawk and Hudson Rail Road. The truck is attached 

 to the locomotive frame by a center pin, but the forward weight of the locomotive is carried by a roller 

 which bears on the frame of the truck. {Smithsonian photo ^6yi6-d) 



had been universally recognized in this country. 

 The truck successfully led the locomotive around 

 sharp curves, the resultant 3-point suspension enabled 

 the machine to traverse even the roughest of tracks, 

 and, altogether, the design did far less damage to the 

 lightly built U.S. lines than did the rigid, imported 

 engines.' 



The truck frame, fabricated from iron straps and 

 castings, was attached to the locomotive by a pin 

 around which it might rotate. At first the weight was 

 received by rollers or chafing pads mounted on the 

 side beams of the truck. However, the friction of 

 these bearing surfaces and their location at a consider- 

 able distance from the center pin combined to restrict 

 the free movement of the truck. By the early 1850's 

 1 Three-point suspension in a 4-2-0 was easily gained— the the point of bearing was transferred to the center 



center plate of the truck and the two bearings of the driving plate, producing a truck that turned more freely.^ 



wheel axle. On a 4-4-0 the center plate served as one point, 



while the fulcrum of each equalizing lever served as the other 



two points, thus providing the desirable and highly stable 



3-point suspension. - American Railroad Journal, 1853, vol. 9, p. 427. 



PAPER 24: INTRODUCTION OF THE LOCOMOTIVE SAFETY TRUCK 



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