Re: roofs, was detail of AAR 1937 boxcar

Anthony Thompson <thompson@...>

Pat Wider wrote:
If I have a car who's tare weight is 50,000 lb. and I load
it with 100 lb. of pillow feathers, I'm hauling 50,100 lb. If I have a car with a tare weight
of 45,000 lb., the same shipment would require hauling 45,100 lb. over the road. 100 lb.
would be well under the load limit of the car. But with a 100-car train of pillow feathers, I
would need less helpers going up Sherman Hill with the lighter cars or I could run maybe a
110-car train of pillow feathers using the same amount of helpers hauling the lighter cars.
Sure, as I said, Pat, the operating guys bought into this. Some did say, as you can read in Railway Age, that rolling resistance was not a strong enough function of weight to make it worth saving a few hundred pounds. The real point was, how did you achieve the saving? and what did it cost?

Also, most of the RME and RA articles on new car designs usually specified the light weight
to cubic capacity ratio of the freight cars. . . It seems the railway mechanical engineers of the
time thought that lighter was better.
Sure, everything else being equal. The question which isn't so easy is, what if lighter is achieved by using a material that corrodes easier? or is thinner and requires extra posts in construction? The mere fact that the burst of "lightweight" box cars after WW II soon died out ought to tell you something. OTOH, of course everyone bought into welded underframes, which save a bunch of weight. I simply dispute the notion that everything to save weight was good.

By the way, ads often state the obvious - Wonder Bras do wonderful things!!!!
No argument, but they also may state unessential things; and they certainly often state things they wish you would believe.

Tony Thompson Editor, Signature Press, Berkeley, CA
2906 Forest Ave., Berkeley, CA 94705
(510) 540-6538; fax, (510) 540-1937; e-mail, thompson@...
Publishers of books on railroad history

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