Reply to "New electro couplers work on test track, not on layout. What gives?"

I've noticed that some couplers are more voltage sensitive than others.  You might also try some dry lubricant to see if that helps.

I'd also look into the voltage drops.  I see around 18.8 volts all around my layout.  If I measure at the yard tracks and then start up a diesel with smoke and six passenger cars, I see a .2-.3 volt drop for the roughly 1 amp draw.  If I were seeing a couple of volts of drop for one train, I'd be concerned.