STREMMATOGRAPH. 91 



an inch, and under the rear drivers it was o. 140 of an inch. In 

 the wheel space between rear driver and front wheel of the 

 tender truck the depression was 0.086 of an inch ; between 

 front tender truck wheels o. 100 of an inch, showing abnormal 

 conditions in the track, and under rear wheel of front tender 

 truck 0.099. 



In the wheel space between the two tender trucks 0.095 

 inches, and under front wheel of rear tender truck o. 1 1 3 of an 

 inch and on the wheel space 0.106 inches and for the rear 

 wheel 0.1 13 inches.^ 



A measurement of a short gauged length, say 5 inches, of the 

 base of the rail under the wheels showed extension, while be- 

 tween the wheels, compression. The measurements were not 

 made in this manner, as it requires more time than can usually 

 be obtained in the main line, but with a micrometer in one posi- 

 tion on the rail each wheel and center of wheel space being 

 stopped over the micrometer. 



Apparent stresses per square inch of the metal for the ex- 

 treme fibers of the base of the rail ran as follows in one posi- 

 tion of the rail for the different wheels and centers of the spaces : 



Tension Compression 

 in pounds, in pounds. 



Front engine truck wheel, 6780 



Center of wheel space, 1530 



Rear engine truck wheel, 534° 



Center of space between rear engine truck 



wheel and driver, Z*^^^ 



Front driver, 9160 



Center of space between drivers, 3050 



Rear driver, 9920 



Center of space between driver and front 



tender wheels, 2290 



Front truck front tender wheel, 3820 



Center of space between wheels, 760 



1 From Report for 1 895, of Tests of Metals and other Materials for Industrial Pur- 

 poses, made with the U. S. Testing Machine at Watertown Arsenal. Mr. James E. 

 Howards, Railroad Track Experiments. By redriving the spikes in the ties, 

 taking up all looseness between the rail and ties, the deflections and stresses were 

 reduced over one- third in amount. 



