PREFACE 



Since the introduction of the quick-action brake, 

 a growing yearly increase in passenger traffic has 

 brought with it a growing increase in the length 

 and weight of passenger trains, in the train speed, 

 and in the frequency of service. Each increase 

 reduced the comparative efficiency of the existing 

 brake system and necessitated improvements. 



In freight service, the increase in the capacity 

 of the cars, the tonnage, and the length of trains 

 augmented the difficulty of brake control to such 

 an extent that new brake apparatus for both 

 engines and cars had to be devised in order that 

 the brake could safely and efficiently control the 

 train. These improvements have been so rapid 

 and have resulted in such a multiplicity of air- 

 brake systems and air-brake apparatus, and the 

 apparatus is made in so many sizes, that today it 

 is a difficult matter to distinguish the different 

 pieces of apparatus and to tell accurately without 

 special information on the subject, to what par- 

 ticular system a piece of apparatus belongs. 



The purpose of this handbook is to supply this 

 special information and to present in convenient 

 form complete reliable data relative to the differ- 

 ent Westinghouse Air-Brake Systems. Among 



