hi,  Building a very small layout and picked up a nice Jupiter steam train with all the cars on ebay.  Got a chance today to test my new stuff, my husbands engine works fine.  (my tester only.)  So no issues with power.  I bought some other train, runs but jerky, probably needs a good cleaning and lube.  But the one I really wanted for this layout is the Jupiter and it doesn't go at all.

So after hitting up assorted youtube videos, it seems between the tender and engine there should be some kind of "hex" coupler?  The other steam train I have is simply wired together.  But this only one video I could find mentions this odd coupler.  Mine has none.  I can see where it should go, but there is nothing so clearly power is not getting from tender to engine.    Any way to replace that?  Or could I simply put a wire in there?

HEY I dug up the only video I could find and he very briefly showed a manual he got with his train.  A picture of the part I need is on there, I froze it and grabbed a screen shot.    Might help explain the odd part I am looking for.