TRIPLE VALVES 



223 



and were equipped with old or high-speed, brake and new, or 

 LN equipments. The brake-valve handle was placed in full 

 release for 6 sec. and then returned to running position. The 

 LN equipment required only 4.4 sec. to raise auxiliary-reservoir 

 pressure to 105 Ib. pressure, whereas the high-speed brake 

 equipment with P triple valves required 27 sec. The slow rate 

 of charging with P triples is due to the fact that the rise in 

 auxiliary pressure cannot exceed the rise in brake-pipe pres- 

 sure. The rapid rise of auxiliary pressure with the LN equip- 

 ment, shows the ability of this equipment to make a number 

 of successive applications and releases with excessive .reduction 

 of the resultant brake-cylinder pressure. 



FIG. 2 



In Fig. 2 are shown the results of rack tests of the old, or 

 high-speed, and new, or LN, equipments, with 110-lb. brake-pipe 

 pressure. This chart shows the curves produced on the brake- 

 cylinder cards by four 20-lb. service applications and releases 

 and one emergency application made 15 sec. apart. With the 

 LN equipment, the brake-cylinder pressure on the fourth appli- 

 cation had only reduced 4 Ib.; with the old equipment, the 

 brake-cylinder pressure dropped to 28 Ib. on the second appli- 

 cation. This difference with the old equipment, was due to the 

 brake-pipe charging to a higher pressure than the auxiliaries. 

 The quick-recharge feature of the L triple valves overcame this. 

 The curves also show that the cylinder pressure reached 

 maximum pressure much sooner with the L triples than with 



