Re: Arcane question of the week

John Barry

A lot lower on a flat car than a house car, with a gondola somewhere in between.  Seriously, the mass distribution propoerties vary not only by car type but by construction.  The trucks were generally a significant portion of the weight, but the underframe and superstructure were also significant portions.  My gut feel is that the center of mass moved downward somewhat as construction methods improved.  Welded Z frame center sills were much lighter than the bolted C channels for instance.  Using the same trucks with less weight above them would lower the CG.  Good question even though most of us don't have the data to answer it.
John Barry
ATSF North Bay Lines 
Golden Gates & Fast Freights 


PO Box 44736 
Washington, DC 20026-4736

From: "'Dave Nelson' Lake_Muskoka@... [STMFC]"
Sent: Saturday, March 19, 2016 12:02 AM
Subject: [STMFC] Arcane question of the week

How far above the railhead would you say is the center of gravity for your average empty STMFC?
Our software team has added curve resistance to the rolling resistance values and while doing so tossed in something else for tipping over at some relationship of curve radius, super-elevation, and speed. I think it’s far too sensitive but I need a  decent center of gravity estimate to make the case.
Dave Nelson

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