. American engineer and railroad journal . small. The wheel was mountedas shown in Fig. 4, and areas of contact witha 75-pound rail were taken at different pointson the tread. Possible changes of length ofthe diameter at right angles to that of the con-tact point were measured by ar-ranged as in the case of the tension tests onwheel No. i. Fig. 2. This wheel was also fur-nished by the American Locomotive Com-pany; both wheel and rail were new. Areaswere taken by means of carbon and tissuepaper as before, and the chains shown in were loose during the tests. Areas of con-tac
. American engineer and railroad journal . small. The wheel was mountedas shown in Fig. 4, and areas of contact witha 75-pound rail were taken at different pointson the tread. Possible changes of length ofthe diameter at right angles to that of the con-tact point were measured by ar-ranged as in the case of the tension tests onwheel No. i. Fig. 2. This wheel was also fur-nished by the American Locomotive Com-pany; both wheel and rail were new. Areaswere taken by means of carbon and tissuepaper as before, and the chains shown in were loose during the tests. Areas of con-tact were taken for various loads up to 80,000pounds. These areas are shown in the follow-ing table: Area midway crankLoad in pin and counter- Area counter-pounds, balance in sq. in. balance, sq. in. 10,000 .36 .33 20,000 .48 .62 30,000 .57 .61 40,000 .68 .73 60,000 .75 .76 60,000 .80 .86 70,000 .91 .96 80,000 Here the areas taken midway between the crank pin and coun-terbalance are smaller than the others, indicating less deforma-. Area crank Average pin, sq. in. area, sq. 1 .35 .346 .61 .603 .63 .603 .74 .716 .81 .77 .92 .866 .99 .96 FIG. 4.—TESTING FOR AREA OF CONTACT BETWEEN WHEEL AND KAIL. The extcnsometers, which measured to i/ioooo of an inch, gaveno indication of any change. Both Rielile and Johnson extcnso-meters were used. Since there was no change in diameter th:increased area obtained at the crank pin must be accounted forby a local bending of the tire and rim. This view is furtherconfirmed by the fact that in this wheel tlie areas over the crankpin were greater than those over the counterbalance, while in t«*i- ^12^- --2W 5^- PlQlgtaed Pace of Balftnoe must Dot be less thsn Vu^ ^ inder Flnlahed Face of Hub; \i^?^.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
