On Tue, May 26, 2009 at 05:03:10PM -0700, Joseph McAllister scripsit: > On May 26, 2009, at 07:18 , Graydon wrote: > >> The fundamental limits on train size are engine traction and drawbar >> strength. >> >> Remember that when starting the train, at some point the engine to >> first >> car drawbar has the entire mass of the train on it; this turns out to >> be >> more of an issue than engine traction. Past a certain size, you get >> an >> awful ping noise as a drawbar breaks, and then you have *two* trains. > > Isn't the drawbar heavily spring loaded, so as to allow the engine to at > least get it's wheels turning a tiny bit before the weight of the train > is slowly, but quickly, pressed upon it? I'm talking only a few inches of > spring compression with a heavy load, but it does change the math a bit.
That effects impulse -- the amount of time involved in applying a force -- but it doesn't change the "you're trying to accelerate the whole train" part. -- Graydon -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
