Re: roofs, was detail of AAR 1937 boxcar


Paul LaCiura <paul.jeseng@...>
 

My opinion regarding the feasibility of the use of aluminum as a railroad
car (freight or passenger) construction material was changed radically when
I did a structural inspection of the passenger car "Civic Center" (former
City of San Francisco car) for the Golden Gate Railroad Museum a few years
ago. They were concerned about the condition of the car and its safety for
use in excursion operations.

I won't go into specific detail of the extensive corrosion damage I found
under the car, but the overall condition could be summed up when I examined
the crash posts and found that they had for the most part turned to powder
beneath the floor line. The builder had specified an "isolation" paint
between the dissimilar materials on the construction drawings. The only
thing that could have prevented this would have been isolation gaskets
between dissimilar surfaces and sleeves around all fasteners to effectively
prevent galvanic contact.

This of course applies to cars built of both aluminum and steel in contact
with each other. I cannot comment on the corrosion resistance of an all
aluminum car in freight service as that is outside my expertise.

Paul LaCiura
San Francisco, CA

-----Original Message-----
From: STMFC@yahoogroups.com [mailto:STMFC@yahoogroups.com] On Behalf Of
Anthony Thompson
Sent: Wednesday, September 21, 2005 2:02 PM
To: STMFC@yahoogroups.com
Subject: Re: [STMFC] Re: roofs, was detail of AAR 1937 boxcar

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 www.signaturepress.com
(510) 540-6538; fax, (510) 540-1937; e-mail, thompson@signaturepress.com
Publishers of books on railroad history




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