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BRAKE CYLINDERS 



CAPACITY OF CYLINDERS 



The capacity of a brake cylinder may be found by applying 

 the following rule: 



Rule. To find the capacity of a brake cylinder, in cubic 

 inches, multiply the cross-sectional area of the cylinder, in square 

 inches, by the piston travel, in inches. 



EXAMPLE. What is the capacity of an 8-in. brake cylinder 

 having an 8-in. piston travel? 



SOLUTION. The area of the cylinder (from table) is 50 1 sq. 

 in. The travel of the piston is 8 in. Hence, the capacity of 

 the cylinder is 8X501 = 402 cu. in. 



The capacity of a brake cylinder is really greater than the 

 amount calculated by this rule, for the reason that there is 

 extra capacity that the rule does not take into consideration. 



CAPACITY OF AIR-BRAKE CYLINDERS 



In freight equipment, the capacity of the auxiliary tube and 

 the cylinder clearance (the space between the brake-cylinder 

 piston and the end of the auxiliary when the piston is in the 

 position it assumes when the brake is released) is not consid- 

 ered, while in passenger equipment, the capacity of the pas- 

 sage in the brake-cylinder head and the cylinder clearance 

 must be added to the cylinder capacity. Usually about 48 

 cu. in. is added to the calculated capacity of a brake cylinder 

 to make up for the cylinder clearance, etc. 



In the accompanying table, the capacities of the standard 

 brake cylinder are given, due allowance having been made for 

 cylinder clearance, etc. 



