. Railway mechanical engineer . ght wheel loads, small flange pressures, slowspeeds, low annual mileage, which prevailed during that time,the wheels would last the entire life of the car. Wheel mile-age obtained under such circumstances is sometimes erron-eously used to indicate the superior service of wheels manu-factured at that time. The ton-mileage, which is the truebasis for comparison, was extremely low as compared withwheel performance at the present time. The 30-ton car, introduced in 1885, was the heaviestcapacity car on any railroad during the time of the WorldsColumbian Exposition a
. Railway mechanical engineer . ght wheel loads, small flange pressures, slowspeeds, low annual mileage, which prevailed during that time,the wheels would last the entire life of the car. Wheel mile-age obtained under such circumstances is sometimes erron-eously used to indicate the superior service of wheels manu-factured at that time. The ton-mileage, which is the truebasis for comparison, was extremely low as compared withwheel performance at the present time. The 30-ton car, introduced in 1885, was the heaviestcapacity car on any railroad during the time of the WorldsColumbian Exposition at Chicago in 1893. Its growth wasvery rapid on all railroads, A chilled iron wheel weighing600 lb. was used under cars of this capacity and wasrecommended as standard in 1904 by the Master Car Build-•ers Association. It was later modified and the weight in-creased to 625 lb. in the year 1909, upon the recommenda-tion of our association. It was not long before the 40-tonand 50-ton car were developed for the coal carrying trade. Fig. 2—Development of the V^heel Flange and the Flange Recom-mended by the Association of Manufacturers of Chilled Car Wheels. and found to be so satisfactory that cars of lighter capacityceased to be built for this service. The 700-lb. wheel wasused under 50-ton cars and was recommended as standardin 1904 by the M. C. B. Association, but afterwards, uponthe recommendation of our association, the weight was raisedto 725 lb., and made standard in the year 1909. Duringthe time intervening a new wheel was introduced of therolled steel type and the steel wheel substituted for the 700-lb. chilled iron wheel weighed a minimum of 750 lb. Cars of 70-ton capacity have already proven successfulfrom every standpoint and are being made in comparativelylarge numbers at the present time. Since the year 1875 the weight of the car structure hasincreased from 18,000 lb. to as high as 65,000 lb., or 260per cent increase. The weight of rail has increased from50 lb. to a
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
