Any way to tighten a coupler so the engine doesn't pull away from the cars. I added a couple of K-Line box cars (they are heavier than my other box cars)and the consist will not stay together,sometimes the cars will pull apart and sometimes the engine will pull away. The engine is an Atlas Trainman GP 15. At the time the engine is pulling 6 cars, it has pulled 6 , 18 inch heavyweights with no problem.
thanks
Brent