TRAIN AIR-SIGNALING SYSTEM 



403 



bell 3 of the whistle. The tone of the whistle depends on the 

 depth of chamber B. The check-nut 4 and cap nut 5 act as 

 locknuts to lock the bell of the whistle in position after it has 

 been adjusted. 



SIGNAL REDUCING VALVE 



The accompanying cross-section of the signal reducing valve 

 shows its construction. The valve weighs 8 Ib. It is adjusted 

 at the works to govern signal-pipe pressure at a maximum of 



40 Ib. per sq. in. and any necessary readjustment must be for 

 that pressure, in order to secure the best results. The piece 

 and reference numbers of the valve and its parts are given in the 

 accompanying list. 



PC. No. Ref. No. Name of Part 



2,360 Signal reducing valve, complete. 



5,182 2 Body, bushed. 



2.369 3 Spring box. 



2.370 4 Supply valve. 



2.371 5 Supply-valve cap. 



2.372 6 Supply-valve spring. 



2.373 7 Piston, includes 8. 

 2,375 8 Piston ring. 



