TRIPLE VALVES 233 



Fig. 1; the brake-pipe pressure was 90 Ib. These curves show 

 the speed-time and speed-distance relations existing through- 

 out the stop. 



A chart showing the progress of air-brake efficiency, as indi- 

 cated by the comparative distances in which a train made up 



FIG. 2 



of a locomotive and six cars has been stopped from a speed of 

 60 mi. per hr. for various types of equipment is given in Fig. 2. 



BRAKE-PIPE VENT VALVE 



The brake-pipe vent valve, here shown, is furnished when 

 ordered with either ET or old automatic (schedule PL) tender- 

 brake equipments. For a complete installation, a 10"X24" 

 reservoir, Piece No. 3,091, is required, and with ET equip- 

 ments, a brake-pipe air strainer with a }-in. side opening. The 

 weight is 27 Ib. This valve is intended for use in place 

 of the triple valve on tenders of engines that are to be used in 

 double-heading or as helpers in a train. The vent valve 

 requires a 10"X24" reservoir. As a vent valve is much less 

 sensitive than a quick-action triple valve, this apparatus 

 can be used wherever brake-pipe venting is desired, with 



