1884.] NEW YORK ACADEMY OF SOIEXCES. 13 



is great diifereuce of opinion as to what is good track. The 

 question must be determined in reference to some standard, in- 

 dependent of personal opinion. To determine this tlie special 

 track inspection apparatus al)Out to be described was designed. 

 Its present construction is the result of many years of labor, 

 experiment and expense. 



A long special 6-wheel truck has been constructed for this 

 purpose, after many experiments with other kinds of trucks, the 

 principle being to use the outer wheels as a definite length of 

 measuring plane, and record the nndulation of the rails in this 

 length by a third intermediate pair of wheels. Mechanical 

 movements communicate only the undulation of the rails to the 

 paper, -Al other mo^'ements of the car Ijody and truck being 

 eliminated. Working from a plane as a liasis of the measure- 

 ments and delineations of the undulations of the rail, gives to 

 them a character and accuracy which is very surprising to those 

 not familiar with the diagrams. In many instances, when the 

 rails have only been in the track two or three years, the exact 

 rail where different brands join is at once seen, owing to some 

 slight difference in methods of manufacture, care in finishing 

 the product and the quality of the steel. 



From the character of the delineation it is at once seen 

 whether the rails are rough and bent, joints low, worn out, or 

 loose on the ties, and whether any permanent improvement 

 whicli can be made by labor or new material is required. 



It was supposed by many engineers that on the best tracks 

 laid with 65 or 67 pound rails, we would find rails without any 

 undulations. This has not been the case under the weight of 

 the car, and is hardly possible, as there are deflections which 

 take place under tlie wheels of the locomotives, springing back 

 to surface when the loads are removed and pass unnoticed until 

 a more or less permanent set in tlie rails takes place. 



The original diagrams of track inspection have demonstrated 

 that the deflections were more than was generally supposed, and 

 has led to the introduction of much stiffer as well as heavier 

 sections of rails. 



The recent 72-pound rail of the Boston and Albany R. R. 

 shows reduced deflections, while the 80-pound rail, five inches 

 high, of the New York Central and Hudson River Railroad, 

 shows still further reduced defle(;tions. 



A comparison of the diagrams from different railroads showed 



