Of course, the electrical connection between loco and tender made it necesarry to add a coupling between the two before there could be any test runs. In order to stay close to the prototypical concepts and to make a long-lasting connection, I wanted to use threaded rods and square nuts. Unfortunately there was not enough room on the loco to use nbw on both ends, so I soldered a square nut onto a threaded rod with a diameter of 1,6mm. That way it looks like a genuine nbw from the outside, but can be screwed into the thick plastic frame.