Brake Tests

203 accompanied by a noticeable shock. This relation between rate of slack action and shock experienced was marked throughout the tests and is particularly noticeable in the case of the service application stops (Figs. 118 and 124 to 126). These show considerable changes in slack, but these changes occurred relatively slowly. Very little shock was felt during any service stops.5 .419. These slack curves, as a whole, are consistent in illustrating the action of the slack progressively throughout the train Some apparent inconsistencies may be noticed, which are due to bunching of the slack previous to the brake application. bunching ot 420. In the case of the electro-pneumatic equipment the more prompt and effective application of the brakes on the cars’ results in the locomotive tending to run out as soon as the brake application becomes effective. The suddenness and degree of shock reupplic from this run out, depends largely upon the percentage of braking g from being used on the cars and locomotive. After this initial adjustment of slack, however, the remainder of the stop is made with tut"ely little movement between cars. When using Lion 1 the locomotive (Fig. 134), the increased locomotive retardation tends to reduce materially the amount of slack action , : .1- produced with the ordinary braking power on the Tooursdrevit (Figs 132 and 133), and for this reason it is desirable locomotive (Figs, equipped with the electro-pneumatic brake. when the cars are 421. Fig. 125 shows the result of the relatively 1 : .: of the UC pneumatic equipment, for which the action of serial action more nearly like that experienced with the PM equipment slack was 120 and 121. wmement. Figs. 119, 422. The locomotive is an important factor in causing on the train. This is clearly illustrated by a comparison sla k action with Figs. 132,133 and 134. Fig. 134 shows how this locomotive dfect is partially but not entirely eliminated, by an increase in itsriest power, so that its retardation is more nearly equal to nit aking from the use of high braking powers on the cars. resu ting 423 While the magnitude of the slack action between cars as shown by the range of movement indicated on the slack cars, as grams, depends to a degree on the amount of force causing such motion it is not proper to assume that the amount of this force is motion with any accuracy by the magnitude of the movement D portrayed cars. The resistances of the draft gear rigging, the buffer springs the adjustment of lost motion continually taking place while the ’train is running, causes at times a considerable movement between dirent cars with very little variation in force and conversely but littl ment may result when a considerable amount of force is being evens between adjacent cars. For these reasons the i: u 18 erted cicatsors the relation between the