File:American engineer and railroad journal (1893) (14572782620).jpg

Identifier: americanengineer71newy (find matches)
Title: American engineer and railroad journal
Year: 1893 (1890s)
Authors:
Subjects: Railroad engineering Engineering Railroads Railroad cars
Publisher: New York : M.N. Forney
Contributing Library: Carnegie Library of Pittsburgh
Digitizing Sponsor: Lyrasis Members and Sloan Foundation

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Text Appearing Before Image:
he M. C. B. Committee as representing passenger and freightservice. SCHEDULE 01 TESTS—BOTH STEEL-TIRED AND CHILLED WHEELS. Soft and Hard Diamond S Brakeshoes.SDeed, miles per hour. . ^-Braking pressure, pounds.^ 65 10,733 6.750 2.79S 41) 6,750 2.798 Soft and Hard Plain Cast iron Brakeshoes. til 6,750 2,798 The braking pressure. 10,733 pounds, represents heavy passengerservice, the pressure 2,798 pounds ordinary freight service, whilethe pressure 6,750 pounds corresponds to medium passenger service.Brakeshoes.—The brakeshoes furnished for these experimentswere of the usual form, to fit the M. C. B. standard head, 13;<jinches in length by 3% inches wide. The face of each shoe wasturned or ground to fit the test wheels which are without taperand approximately 33 inches in diameter. The shoes were num-bered from one to eight, as follows:Shoe No. 1 and No. 2, soft Diamond S.No. 3 and No. 4, plain soft cast iron. No. 5 and No. 6, hard Diamond S. No. 7 and No. 8, plain hard cast iron.
Text Appearing After Image:
Figs. 1 and 2. wheel is 103.5 inches while that of the steel-tired wheel is 103,3inches. Experiments.—The testing mxchine has not been used since thelast tests mile by the M. C. B Association, and no changes iu theapparatus have been nude. Thesaui: precautions wern taken inmaking the present tests, and the same methods followed, whichwere used in former work done on this machine. A comparison of the tests made on steel-tired and chilled wheelsshows that the difference between the average mean co-efficients offriction obtained with the same shoe upon the two wheels areslightly higher in the case of the chilled wheel, excepting shoe No.2 at 40 miles per hour initial speed and 2,793 pounds braking pres-sure, where the higher average was got on the steel wheel.It would appear, therefore, that practically the same results couldbe expected, as far as friction is concerned, from steel-tired andchilled wheels, with shoes similar to those tested. A comparison of the co-effic;ents of friction

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