File:Train resistance - a consideration of its elements and a discussion of experiments made with the university dynamometer car (1900) (14735353756).jpg

Identifier: trainresistancec00kueh (find matches)
Title: Train resistance : a consideration of its elements and a discussion of experiments made with the university dynamometer car
Year: 1900 (1900s)
Authors: Kuehn, Alfred Leonhardt Eddy, Clarence Leroy
Subjects: Railroad trains Theses
Publisher:
Contributing Library: University of Illinois Urbana-Champaign
Digitizing Sponsor: University of Illinois Urbana-Champaign

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
ich is as near perfect lubrication as it is possibleto have. V/e see from plate ) that between pressures of 100 and 500pounds per square inch the resistance is practicallyjconstant. There-fore between these pressures we have practically perfect lubrication Pressures found on freight car journals may be estimatedfrom the following table of weights kindly furnished by a prominentwestern railroad(and which represents average practice. Kind of Oar Weight Pressure per sq. in. on Jour. lbs. Empty Loaded 20-ton capacity box 26600 95 lbs 258 lbs or tt ft m ^ u 27500 81 228 22 ii 29700 88 264 25 „ furnit. 30000 88 236 1° „ 35800 105 282 20 ,, stock 24900 go 232 OC ii H ft •••••••• «-/<-►-/ ~5 „ 26800 70 226 30 u 32000 04 271 20 „ fri*it 29200 10d00 54. 201 50 20300 66 236 40 ■ 28700 64 242 ■ coal 24100 36 ... 229 25 ■ 25300 74 *22 30 » ■ 26600 7S 255 40 » ■ 31300 71 265
Text Appearing After Image:
16 This table gives average values for pressures on journal3 :for emoty cars 85 pounds per sq. in,, for loaded cars 245 pounds persq. in. ,-approximately a ratio of 1 to 3. Tower found (see p.13) forthese pressures and a speed of 24 miles per hour,the coefficients0.0064 and 0.0022 respectively,corresponding to resistances of 1.23and 0.44pounds per ton. How nearly these values obtain in actual practice is notdefinitely known; when estimates are made, the part of the totalresistance which is journal friction is assumed on -ere judgement.The common theory is that al1 the resistance which arises about thewheels is journal friction. This amounts to saying that the lubrica-tion on cars is about one-sixth as efficient as a bath of oil,or ispractically that obtained by Tower for a pad which gave an oil filmon the journal barely perceptible to touch. That car lubricationis better than this can not be doubted; in fact for passenger cars and well kept freight cars, we always find a heavy film of

Note About Images