Re: Flat Car Load Placement

Bruce Smith

Nelson, Folks,

On Aug 14, 2019, at 7:36 AM, Nelson Moyer <npmoyer@...> wrote:

That suggests that since a concentrated load in excess of 50000 lbs. can't be distributed or placed over one of the trucks, the shipper would need a car with a higher center load capacity.

EXACTLY!  So, the deal here is that the optimal loading position for a flat car for ride characteristics is the center of the car, BUT, almost all flat cars were restricted to significantly less than their capacity if the load was carried on the center of the span. What we have are two competing issues. NOTE, that a load, at the center of the span, placed on stringers or other supports at 1/3 and 2/3 of the span is NOT loading the center of the span. There were a few, very specifically and typically short cars that were designed to carry the full load at the center of the span. The Milwaukee Road welded gun flats (ancient Roundhouse car) and the PRR F22/23 “gun flats” are examples.

For modeling, I guess load weight is a moot point, as few of us calculate load weight and assign a load to a specific car on that basis.

Hmmmm… I do.. and it bugs me when I see obvious fails, such as the use of a 70 ton flat to carry one M4 Sherman tank (which is too little load for efficient car use).

I guess the best alternative to load weight calculation is to use photos of actual loads together with the AAR and ORER loading instructions as the inspiration for out loads. Actually, that approach can result in some improbably loads like the M&StL culvert flat car load Clark Probst posted to the Proto-Layout group that must have challenged height clearance limits. I suspect a modeler would be ridiculed for building a load like that. Sometimes truth is stranger than fiction.


Bruce F. Smith            
Auburn, AL
"Some days you are the bug, some days you are the windshield."

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