HOSE, COUPLINGS, AND FITTINGS 385 



equipments and for repairs. The old-style type F and type 



H dummy couplings are furnished on special order only. The 



piece numbers are as follows: P 



dummy coupling, new style, 20,806; 



H dummy coupling, new style, 



20,810; F dummy coupling, old 



style, 2,133; and H dummy coupling, old style, 2,134. 



CLEANING TOOL 



The piece number of the coupling-groove cleaning tool, 

 which is shown in Fig. 4, is 11,479. 



M. C. B. SPECIFICATIONS FOR AIR-BRAKE 

 HOSE 



In 1901, specifications and tests for air-brake hose were 

 adopted as recommended practice; they were advanced to 

 standard in 1903, and revised 1905. 



"1. All air-brake hose must be soft and pliable, and not less 

 than 2-ply nor more than 4-ply. They must be made of rubber 

 and cotton fabric, each of the best of its kind made for the pur- 

 pose. No rubber substitutes or short -fiber cotton to be used. 



"2. The tube must be hand-made, composed of three calen- 

 dars of rubber. It must be free from holes and imperfections, 

 and in joining must be so firmly united to the cotton fabric 

 that it cannot be separated without breaking or splitting the 

 tube. The tube must be of such composition and so cured as to 

 successfully meet the requirements of the stretching test given 

 below; the tube to be not less than &-in. thick at any point. 



"3: The canvas or woven fabric used as wrapping for the 

 hose to be made of long-fiber cotton, loosely woven, and to be 

 from 38 to 40 in. wide, and to weigh not less than 20 and 22 oz. 

 per yd., respectively. The wrapping must be frictioned on both 

 sides, and must have, in addition, a distinct coating or layer 

 of gum between each ply of wrapping. The canvas wrapping 

 must be applied on the bias. Woven or braided covering 

 should be so loose in texture that the rubber on either side will 

 be firmly united. 

 26 



