TRIPLE VALVES 



pressure of the first and the one-hundredth cars. It will be 

 noted that the fall in pressure from the fiftieth to the one-hun- 

 dredth car was practically uniform, showing that the reduction 

 was due more to the expansion of the air in the brake pipe 

 back of the fiftieth car rather than to a flow of the air. This 

 shows that enlarging the outlet from the brake pipe at the 

 brake valve will not hasten the application of the brakes. 



JO 





FIG. 2 



Also, it shows the necessity of the quick-action feature and the 

 quick-service feature of the K triple valve for trains of this 

 length. 



The second test was to determine the fall in brake-pipe 

 pressure on individual cars of a one-hundred-car train, 4,000 ft. 

 long; type K triple valves were cut in; and a service reduction 

 was made. The results of this test are shown in Fig. 2. Com- 

 paring these curves with those in Fig. 1, shows how the local 



