Originally Posted by
BillCobb
The problem with this analogy is that nowhere in traditional vehicle dynamics straight line or cornering equations are displacement constraints (other than where is the ground). Vehicles initiate a turn because of a moment imbalance and continue to yaw and sideslip until this moment (whether from a front or rear steer angle or a wind gust or a tire induced imbalanced, etc.) is nulled. Depending in your point of view, the final resting trim can either be favorable or unfavorable relative to walls, trees, lakes, rivers or snow banks.
As an added observation, may I point out that REAL train's couplers are body mounted, not truck mounted (as your model trains are assembled). There is a huge advantage to this when negotiated turns at speeds well above a posted speed limits set by bank angles. Yes, train wheel flanges are a displacement constraint and the resulting cornering g levels from flanges plus coupler moments can be almost unbelievable. GM has an instrumented automobile carrier car that often rides along in coast to coast deliveries. The dynamic forces read were eye openers and resulted in major changes to batteries, wheel bearings, and vehicle tie down methods and systems. They are often higher than those experienced during abusive driving! GM uses the results to coax rail owners to repair portions of the route or avoid some portions altogether thank you.