[QUOTE=Ryland;317461]Trains and RV's tend to have a lot more bulk to them and are a lot smoother then passenger cars.
Are you kidding? Apparently you have never ridden a caboose on the rear of an 80-130 car freight train. I have been
knocked down by the slack running in and shortly after stood back up when it ran out (luckily the train didn't break in two).

True, they have more bulk but most autos ride much better unless you are comparing to a passenger car.