148 TRANSACTIONS OF THE [FEB. 1, 



for many railroad people still treat the roadbed as though it 

 were wholly an inelastic body, and permit the waves of pressure 

 to be transmitted to it in amount far in excess of its elasticity, 

 so that deformation takes place,which must be repaired by surfac- 

 ing at least 



The elasticity of the roadbed is not likely to be uniform per 

 mile for the entire road ; some portions will take up and carry 

 3,000 pounds per square foot without injury, while other por- 

 tions, being more plastic will not carry 2,000 pounds without set 

 and deformation. 



The drainage of the roadbed must be very efficient at all times, 

 as a reduction of a few per cent, of moisture decreases the plas- 

 ticity and increases the elasticit}'. This feature can ndw be traced 

 on the diagrams. The ballast under the ties, when dry and ot 

 good quality, is supposed to reduce the pressure from the tie to 

 the roadbed, inversely as its depth. I think the estimate too 

 high for general practice, and have shown the waves of pressure 

 transmitted from the ties through the ballast to the roadbed as 

 less in one of the lantern slides. 



One lantern slide was shown, containing the condensed dia- 

 grams of the inspection of the New York Central & Hudson 

 River R. R. for 1895 as a plain line and those for 1801 as a 

 broken line. 



The diagrams for 1895 show the greatest improvement of any 

 yet obtained, and they are compared with those of 1891, instead 

 of 1894, as those dates afford the most valuable comparisons be- 

 tween the stability of the track for different sections of rails; 

 they also give comparisons between suspended joints and three- 

 tie supported joints. 



On the Hudson Division, in the diagrams for 1891, from New 

 York to Mott Haven, the first five-inch 80-pound rails laid in 

 1884, were still in service. They were laid with 22-incli splice 

 bars, suspended joints, and were replaced by 100-pound rails in 

 1892. 



From Spuyten Duyvil to Peekskill the five-inch 80-pound rails 

 were laid in 1886 and 1887, with 22-inch splice bars, suspended 

 joints, and were replaced by 100-pound rails in 1894. The condi- 

 tion of the track in 1891 on the 80-pound rails averaged some 

 8 lines higher than the track from Peekskill to Albany, laid witlj- 

 the five-inch 80-pound rails and Col. Katte's three-tie supported 

 joint. 



From the condensed diagrams it will be seen that from Peek- 

 skill to Albany the track has been maintained under its heavy 

 traffic, practically on the same lines for four years — a result not 

 probable with suspended joints. 



