190 



CONTiNUOUS EATLWAY BRAKES. 



the brake cannot be got " on " nearly as quickly as where 

 compressed air ia used. 



The application of the brakes might be hastened by apply- 

 ing " automatically " opening valves at various points in 

 the train-pipe for admitting air ; but tlie chances of some- 

 thing going wrong would bo likewise increased. 



This brake is very extensively used ; and it gives the 

 driver complete control over his train. 



The Steel & McInnes Bkake. 



An air-compressing pump on the engine forces air along a 



continuous train-pipe to the top and bottom sides of the 



brake piston, working in a cylinder, with which each 



carriage is supplied. The lower part of these vertical brake 



cylinders is enlarged to form an air vessel. When the 



brake-piston is in unstable equilibrium, the brakes are " off." 



To apply the brakes, air is discharged from the top side 



of the brake-piston, when the air below it and in the air 



vessel expands, and pushes up the piston, thus applying the 



brakes. The piston rod passes through the lower end of the 



vertical cylinder, and is there connected with the brake 



lovers l)y a connecting rod. The piston rod passes through 



a stuffing box and gland, which, if not kept properly packed, 



gives rise to trouble in practice by reducing the pressure 



below the piston. 



The McInnes brake comi)lies with the Board of Trade 

 requirements. 



It is not used in England, but ia in Scotland, though not 

 extensively. 



The enormous quantity of air which has to be discharged 

 from the top ends of the cylinders and train-pipe when the 

 brakes are to be applied, and then re-supplied when the 

 brakes are to come " off," renders it slow in action. 



