STREMMA TOGRAPH. 95 



rails under the moving train ; nevertheless it occurred, but to 

 much less extent than on the 65-lb. rails. [See Plate XIL, 

 Fig. 2.] 



On the diagrams of the heavier rails of recent years, the un- 

 dulations per mile on the 80-lb. rails have been reduced to less 

 than three feet, and on the lOO-lb. rails to less than two feet; 

 as measured by my car, the rails being in good surface ; the ties 

 showing but little abrasion under the rails. 



In 1883 it was considered by many that a 5 -inch 80-lb. rail 

 was stiffer and heavier than necessar}-, while others thought it 

 would provide for the future development of the railways for all 

 coming time. , 



The rails once in the track furnished a practical demonstration 

 of the value of stiffness in rails and soon led to an increase of 

 speed and heavier equipment, increasing the fibre stresses in the 

 80-lb. rails over that for which they were designed to sustain. 



In March, 1892, my 6-inch lOO-lb. rail section was rolled, the 

 first to go into service in the United States, to again reduce the 

 fibre stresses in the rails to meet requirements of increasing 

 traffic. To date there are several thousand miles of lOO-lb. rails 

 in use in this country. 



In the last decade all of the Eastern and many of the Western 

 trunk lines have been laid with stiff, rails for the purpose of 

 keeping the fibre stresses in the rails down to safe and economic 

 limits, though this feature of the matter has received but little 

 discussion. 



In 1888 in connection with Mr. James E. Howard, of the 

 Watertown U. S. Arsenal, I had one of the Boston and Albany 

 passenger locomotives weighed and ran it onto rails in the main 

 track, the upper side of the base of the rail having been pre- 

 pared with prick punch marks practically 5 inches apart, the 

 space having been measured with a micrometer to i 10,000 of 

 an inch. The measurements were repeated after the locomotive 

 was on the rails to ascertain the compression of the base of the 

 rail between the wheels and the elongation under the wheels. 



From the results the apparent stresses in the rails were com- 

 puted for the static loads which were probably too low as the 



