Figure 23. - Cyundi r head with valve b<>\ 



removed. 



Figure 24. — Bottom ol valve box with sli< l<- 

 valve removed. 



25 and 26. — Cylindir with valve box removed, > t n ■ \ \ i 1 1 ■_; val 



type frame than any other (I'm-. 18,27). While the 

 simple bar frame enjoyed the greatest popularity in 

 the last century, riveted frames were widely used 

 in this country, particularly by the .New England 

 builders between about WHO and WitiO. The riveted 

 frame was fabricated from two plates of iron, about 

 %-inch thick, cut to the shape of the top rail and the 

 pedestal. A bar about 2 inches square was riveted 

 between the two plates. A careful study of photo- 

 graphs of Hinkley and other New England-built 

 engines of the period will reveal this style of construc- 

 tion. The frame <>)' the Pioneer differs from the usual 

 riveted frame in that the top rail is 1 s 4 inches thick by 

 IV inches deep and runs the length of the locomotive. 

 The pedestals are made of two 3 s -inch plates flush- 



riveted to each side of the top rail. The cast-iron 

 shoes which serve as guides for the journal boxes also 

 act as spacers between the pedestal plates. 



The bottom rail of the frame is a l' s -incli diameter 

 rod which is forged square at the pedestals and forms 

 the pedestal cap. The frame is further stiffened by 

 two diagonal rods running frorn the tup of each truck- 

 wheel pedestal to the base of the driving-wheel 

 pedestal, forming a truss. Six rods, riveted to the 

 boiler shell and bolted to the frame's top rail, 



strengthen the frame laterally. Four of these rod- . an 

 be seen easily as they run from the frame to the middle 



of the boiler; the other two are riveted to the underside 

 of the boiler. The attachment of these rods to the 

 boiler was an undesirable practice, for the boiler shell 



PAPER 42: THE "PIONEER" OF 1851 



263 



