Box Cars

[Anonymous]

My train with 10 box cars goes around, up a grade into a reverse loop, returns down the grade thru a tunnel, under the elevated loop, and into another reverse loop. No matter what engine is pulling this consist......the Doors on the Box Cars start to open. Seems that the right side Doors tend to open more than the other side........However they never tend to close !

Does someone have an explanation ??[?][?]