I opened a couple new MTH crossovers tonight. Can anyone tell me: what is the purpose of the center hub? I stuck a screwdriver in the slot and turned it. It clicks to the next spot. It doesn't seem to do anything other than "click". ???
It is the "improved electrical design" mentioned on the box. It disconnects (middle rail) electrical continuity between adjacent legs of the crossover which permits each portion to be controlled via different transformers or operate at different voltages. Naturally, isolation of each leg makes reliable operation of two independent loops crossing "at grade" much easier. This thread briefly discusses its function and reliability.
I think this actually does represent an improvement from the original design, which never made any sense to me. Now if MTH would just make a 45 degree crossing!
USM, thanks. Since this is my first experience with these (and I haven't even used them yet), I'm not sure what needed improving. Prior to discovering the center hub, my only concern was the train navigating the crossover smoothly. Were there electrical issues with the old crossovers? I agree that a 45 would be fanstastic.
The only electrical issue with the original crossings is the fact that two tracks that crossed were no longer electrically isolated. Okay for a figure eight layout, but not for two separate tracks. Kind of surprising one of the original manufacturers didn't offer a crossing with at least the possibility of electrical separation of the crossing tracks.
I see now. Thanks, Kirk.