#1.  They are the knuckle couplers. 

#2.  I do not know if they are the older Bachmann coupler.  Is there a way to check this out? 

#3.  No, I do not have a coupler height guage and I did get down to eye level when this happened.  One car would stay hooked up to the engine, but the others would break away.   Also, this was on a flat surface - no slope.  I did notice that when I checked the height of the coupler connection, the engine coupler wanted to raise up over the cars coupler.

Thanks

I'm just getting started again after many years and got the HO McKinley Explorer for my grandsons.  I set it up and ran it, but I fofund that on a right hand turn, the cars broke away from the engine.  I switched cars to see if there was a problem with the coupler on one car, but they only broke away on right hand turns.  I see that Bachman has many couplers available. 

What do you suggest?  The couplers are the standard ones.  They came with set when shipped.