Union Pacific BE-70-1 & Newton's 2nd Law

Here is Union Pacific postal storage - express box car built by St. Louis Car in 1964.  It seems like this UP class BE-70-1 stretches out in the distance.  Noticed the LD LMT (Load Limit) when it's placed in a freight vs. a passenger train.  Ah,  remember your high school physics of Newton's 2nd law of motion?   F = MA.  The Force acting on the object is equal to the Mass (like weight) times the Acceleration of the object.  So an object going at passenger train speeds carry much more force with it than at freight train speeds.  Therefore, a higher load limit is allowed for this express car if it was in a freight train consist.   Enjoy.  

Ps. Be sure to reserve your new batch of PC&F box cars with your dealer or direct this Sat!