I just purchased a Genesis F7 (A and B units), DCC and sound. A really neat engine. However, I cannot seem to run both together. The engine runs very well, but, when I attach the second unit, it seems that the second unit is "dragging" down the engine. I know I have overlooked something, but can't seem to figure it out. BTW, i am running this engine with a Digitrax Zephyr Xtra. Can someone help this old man that is also a newbie? (Be gentle!). And, thanks.