Re: roofs, was detail of AAR 1937 boxcar

Patrick Wider <pwider@...>

--- In STMFC@..., Anthony Thompson <thompson@s...> wrote:
Traffic people knew that the cars were rarely loaded to
capacity, so the claim of "converting the saving into revenue load"
was, statistically, silly. And of course US Steel wanted to sell
premium steels, if they could just persuade railroads that they needed
them . . .
I don't think the case is so simple as you state, Pat, certainly
not prior to, say, 1960. Indeed, if "everyone" knew this, those ads you
quote wouldn't have needed to press the point.

I don't see the logic in your point. 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.
Wouldn't the lighter cars produce a meaningful savings for the railroads? And wouldn't
that be obvious? It seems for some railroads such as the Milwaukee Road, they also
needed more cubic capacity, hence Nystrom's design for the 50000-series of 50' box cars.
They were the "high-cube" box cars of their era (5,157 cu. ft.). But the savings I describe
above would still apply even for these cars if they could be built lighter (less mass).

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 (in addition to the load limit to gross load ratio).
For example, it was 9.35 lb. per cu. ft. for the Milwaukee 50000-series cars, a low value
for the time. (RME, Dec. 1941, p.508). It seems the railway mechanical engineers of the
time thought that lighter was better.

So it still seems simple to me. It's F = MA. As I said, "lightness is good" (assuming the
new designs don't fall apart - Note I also said durability was a desirable characteristic). By
the way, ads often state the obvious - Wonder Bras do wonderful things!!!!

Pat Wider

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