19G 



CONTINUOUS RAILWAY BHAKES. 



communication between the accumulator and the brake 

 cylinders. This occurs when the train-pipe becomes broken, 

 the coil spring, then unbalanced, forces over the valvo 1, 

 and opens a passage from the accumulator to the brake 

 cylinder through the port 2, the brakes being applied. This 

 brake is not used ; it is an example of an able and ingenious 

 endeavour to cope with the difificultics that l)osct the ])rafiti- 

 cal solution of the brake-question. 



The principle of the brake closely resembles " Westing- 

 house's." The trial brakes answered well ; but the use of 

 water barred the way to the general adoption of Barker's 

 hydraulic automatic brake. 



Tliero is one point which has not been referred to in 

 dealing with air and vacuum brakes of the automatic di- 

 vision. 



Tills is the "leak off" device, adopted in the "Clayton 

 and Smith" brakes, for allowing the brake to come "oif" 

 after it has been " on " from 80 seconds to 120 seconds. 



It will be seen from tlie principle of the automatic brakes 

 that the brakes go "on" when a hose coupling becomes un- 

 done, or when air is admitted to the train-pipe for applica- 

 tion of the brakes. Now, in the " Automatic Vacuum " 

 brakes, where there is no "leak off" hole in the piston, the 

 brakes will remain "on" until released by the "ejector" 

 withdrawing the air from the train-pipe, or until the driver 

 allows air to flow to the top as well as to the bottom side of 

 the brake piston, by means of the release valvo and lever 

 attached to each cylinder. To release, the guard pulls the 

 cord connecting the release valve levers, which pulls the 

 ball away from its seat, allowing the air to flow to the top 

 side of the piston, thus balancing it and releasing the 

 brakes. 



Now this release valvo device is only provided to admit of 



