On 3 Dec 2020 at 22:42, Glenn Brooks via EV wrote: > There are actually three forms of resistance commonly associated with rail > transport: 1) train resistance - the loaded weight of the consist and > locomotive; 2) grade and curvature resistance imparted by friction between > the rails and wheels, and 3) vehicle speed.
It might be because I wasn't a physics major, but that list confuses me. Raising a mass requires energy, but you recover that energy when the mass falls. So that doesn't seem to me like it'd be a source of loss. Isn't grade and curvature resistance just a change in the amount of friction between wheels and rails, caused by the changing contact area between them? Finally, I don't see how speed by itself is resistance, though for sure, velocity will affect wind resistance. Maybe that's what you mean? It seems to me that in railway transport, we're talking about the same losses any vehicle has - to friction and aero resistance. I'm afraid I don't fully understand the nomenclature here, or how it helps analyze the problem. Obviously I'm missing something - like maybe the point? Can anyone help? Thanks. David Roden, EVDL moderator & general lackey To reach me, don't reply to this message; I won't get it. Use my offlist address here : http://evdl.org/help/index.html#supt = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = A developed country is not a place where the poor have cars. It's where the rich use public transportation. -- Gustavo Petro = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/index.html INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
