100 - DUDLEY. 



The record curves of the stresses of compression and tension 

 of the metal in the rails between and under the wheels consist of 

 a series of very much flattened upper branches for the compres- 

 sion between the wheels with very much sharper lower branches 

 for the tension. [See Plate X., Fig. i.] A similar record is 

 obtained by having a particular portion of the rail stressed by a 

 moving train as shown by the enlarged records of the Strem- 

 matograph on the screen of two trains. [See Plate X, Fig. 2.] 



After the Stremmatograph is attached to the rail a reference 

 line is ruled on the metallic strip and then the scriber point is 

 moved a few thousands of an inch, the instrument started and a 

 line about J^ of an inch long ruled, w^iich in reality becomes 

 the measure for a median line, and the distance to the reference 

 line measured by the micrometer. When the train is within a 

 rail length of the instrument it is again started ; the metallic 

 strip moving at right angles to the rail ; the scriber point re- 

 cording the mean molecular compression and extension of the 

 base of the rail usually for five inches in length. 



The upper lines are the records for the 5 -inch 80-lb. rail on 

 inside of curve as already described in track No. 2. The rail 

 has a very wavy surface, the stresses being very largely aug- 

 mented owing to that feature. The locomotive w^as No, 888, 

 Class I, of the N. Y. C. & H. R. R. R., drawing five Wagner 

 Palace Cars, ; speed 40 miles per hour and being rapidly accel- 

 lerated. The extension of the metal in the base of the rail due 

 to the the several wheel loads of the locomotive and car can be 

 traced, those of the locomotive being very distinct, while the 

 compression of the metal between the wheels can also be seen. 



The rail was the inside one of the curve, track No. 2, in loca- 

 tion already described. The rising of the rail in front of the 

 pilot is plainly seen, the stresses of: 



Compression being Ij4I7 lbs. 



Tension under front truck wheel 13,070 



Compression between front and rear truck wheel 3)069 



Tension under rear truck wheel 12,579 



Compression between rear truck wheel and front driver. 5,433 

 Tension under front driver 3Ij4I5 



