ENGINEER'S BRAKE VALVES 113 



PC. No. Ref. No. Name of Part. 



6,672 15 Gauge and equalizing reservoir T. 



OPERATION OF G-6 AUTOMATIC BRAKE VALVE 

 Release Position. Three views of the G-6, engineer's, auto- 

 matic, brake-valve are shown in Figs. 1 and 2. When the 

 brake valve is in release position, main-reservoir air is free 

 to pass out into the brake pipe. As the brake-pipe pressure 

 increases, the triple pistons are forced to release position and 

 the auxiliaries are charged. While the air is passing through 

 the brake valve into the brake pipe, it is free to pass down 

 through the rotary valve into the chamber above the equal- 

 izing piston, and thence out to the equalizing reservoir 

 through the T fitting 15. In release position, one large port 

 leads from the main reservoir to the brake pipe, and two small 

 ports lead to the equalizing reservoir. 



A small port r, called the engineer's warning port, is drilled 

 through the rotary valve in such a position that, when the 

 latter is in full-release position, this warning port is directly 

 over the exhaust port in the rotary seat. Main-reservoir 

 air on top of the rotary blows through this small warning 

 port into the exhaust port, and the sound of the escaping air 

 is heard by the engineer. This is to warn him that he must 

 not leave the valve in full -release position too long. 

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