I purchased the ATSF VL stock freight 3 pack. The car with sound has a very stiff truck on opposite end of the electro-coupler. Stiff enough that it will derail on any turnout if that truck is the last truck on the train (not coupled to anything.) Coupled up the car behind exerts enough force, apparently, to keep it from derailing.
Do I remove the truck and inspect or do I contact Lionel for service -- since it is brand new?