1907 - Steel vs. Cast Car Wheels

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Roanoke Times - November 27, 1907

STEEL VS. CAST CAR WHEELS

   The recent accident on the Norfolk & Western between Roanoke and 
Lynchburg, in which the flange on a coal car broke and precipitated 
the car against a passenger train, side-swiping the passenger coach 
and producing a destructive wreck, affords a subject for an editorial 
in a recent issue of the Railway Age, on the relative merits of cast 
and steel car wheels. Its says:
   "Another illustration of the importance of making freight cars 
safe and maintaining them carefully was given in the accident on the 
Norfolk and Western, near Roanoke, Va., on October 12. A freight 
train and passenger train were passing in opposite directions when a 
broken flange threw a coal car against the passenger train, 
demolishing three passenger cars; 25 coal cars were badly damaged, 
one person was killed and some others were injured. Weak flanges on 
cast-iron wheels are becoming a frequent source of danger, so much so 
that the manufacture of solid steel wheels for freight service is 
growing rapidly, and they are being ordered by the thousands. The 
increase in the size of the flange of cast wheels should improve 
conditions to a slight degree, but not too much should be expected 
from it. M. C. B. Rule, No. 10 requires the renewal of wheels under 
cars of 80,000 pounds capacity or over when the flange and the flat, 
vertical surface extends more than seven-eighths of an inch from the 
tread or it the flange is less than one and one-sixteenth inches 
thick, and steel-tired wheels are condemned if the flange is less 
than one inch thick. There is a strange inconsistency in assuming 
that a cast flange one and one-sixteenth inches thick is equivalent 
to a steel flange one inch thick, while it is well known that the 
tensile resistance of the two metals is about one to four and that 
the shearing resistances have about the same ratio. The Purdue tests 
made to show the strength of the flanges of cast-iron wheels showed 
the resistance of three wheels which had been eight months in service 
to be  60,000 pounds and that of new wheels with the large flange 
103,000 pounds. The normal strength of cast flanges may be taken at 
70,000 pounds. The experiments made by George L. Fowler on the 
strengths of flanges of steel wheels showed them to have a shearing 
resistance of 526,000 pounds.

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- Ron Davis, Roger Link