. The Street railway journal . , illustrates this point, as at low ratesof speed from to o, it closely approaches the brakecoefficient at the same speeds. In Fig. 4, which presents similar curves for the operationof the hand brake, the same high rate is shown, and the sameremarks are applicable. These results may appear abnormal,but the fact that the data from which these extremely highrates of retardation were figured were taken by an automaticelectric recording apparatus, and the figures and curves care-fully gone over and checked, justifies their insertion in the faceof possible
. The Street railway journal . , illustrates this point, as at low ratesof speed from to o, it closely approaches the brakecoefficient at the same speeds. In Fig. 4, which presents similar curves for the operationof the hand brake, the same high rate is shown, and the sameremarks are applicable. These results may appear abnormal,but the fact that the data from which these extremely highrates of retardation were figured were taken by an automaticelectric recording apparatus, and the figures and curves care-fully gone over and checked, justifies their insertion in the faceof possible criticism. In reviewing the foregoing test data, the extremely smallcost of power consumed for braking, as compared with thetotal, will be apparent. This emphasizes the fact that whenthe adoption of power brakes is under consideration, the costof power for their operation is so small as to be almost negligi-ble, and need hardly be considered a function of the it is remembered that the distance of the round trip on. A comparison of the two retardation curves in Figs. 4 and 5shows a marked difference in their characteristics, attention towhich was called in the preceding paragraph. As the initialvelocity of the cars was the same in each instance, their per-formance under the influence of the two brake systems is ofinterest. From Fig. 4 it will be noticed that the car using ahand brake ran a distance of ft. before stopping, and thatthe time required for the stop was seconds after the applica-tion of the brake. In Fig. 5 it is shown that a car equippedwith an air brake stopped from the same initial speed in 73 ft., seconds after the brake was applied. In other words, theair brake stop required but per cent of the distance, per cent of the time of the hand brake stop. The hand brake curve here presented represents an emer-gency stop, under favorable conditions, and as the air brakestop was similarly made, the comparison here indicated can becons
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
