Instead of the normal way of wiring a reverse loop with its own power supply and having 2 gaps in the rails, why couldn’t you just put one gap in with a plastic connector and use one power pack? I tried to put in a picture but my pop-up blocker wouldn’t let me.
Welcome to the forum. [#welcome] You’ll get lots of good advice and help here.
I’m assuming you’re talking about DC control and not DCC. I don’t know about a reverse loop having its own power supply being “normal”–I’ve never heard of that and it would be a hard job to match the voltages of the two power supplies when a train crossed the boundaries. However you must have gaps in both rails at both frog ends of the turnout leading into the loop. That’s 4 rail gaps. Otherwise you’ll have a short circuit. You will need two reversing switches external to your power pack or throttle. Consider the reversing switch on your throttle as the locomotive’s “gearshift” to change between forward and reverse. One of these reversing switches powers the loop track, the other powers the rest of the layout. When entering the loop, you set its reversing switch to match the polarity of the rest of the track. While the train is in the loop, you throw the turnout and flip the other reversing switch to change the polarity of the rest of the layout. It’s really not very complicated.
Hope this helps.
Nope, because whe the train passes over the gap, the circuit is complete through the loco. Look at it as if the insualtor was not there, because that’s how it is whent he loco passes over the boundry. Trace the path of the circuit from one power pack terminal to the other. It will pass from one terminal to the other without ever having to pass through the motor in the loco or any other load. This is a short circuit.
–Randy
How about DCC? There are reversors available for DCC - what do they do? I am thinking the reversor circuit only changes the polarity of the reversing section (again, though, with gaps at both ends). This is good timing, because I’m about to set up a reverse loop. In my case, my “loop” is really one whole end of my layout, where thery may be other loco’s operating. I am using DCC, and I’m thinking the loco’s will all tolerate the polarity change. True?
BTW, I’ll probably try a simple DPDT switch first, and I have no sound engines (yet).
Jim
Reverse loop controllers for DCC need both rails to be insulated at both ends of the reversing section, just like for DC. The difference with DCC is that the DCC track power conveys no actual polarity information that controls the direction fo the locomotive. It’s actually a square wave signal so the correct term is ‘phase’ not polarity. Whent he train leaves the loop, the right hand rail in the loop side will be on say the negative half fo the square wave, and the right hand rail ont he mainline side of the gap will be in the positive half. Again - short. The DCC autoreverse senses this and reverse the ‘polarity’ (really the phase) of the track in the loop so that it matches. You cna do this because the DCC signal itself is not what tells the train the direction to go - it matters not one whit to the locomotive if the right hand rail is on the positive side fo the wave or the negative side, if the command to the decoder is ‘forward’ it moves forward regardless. So you can flip the ‘polarity’ under a running train and nothign happens. Try this in DC and the train would instantly reverse direction. You can use the same kind of DPDT toggle arrangemetn to work a DCC reverse loop, but the whole idea of DCC is you don’t have to flip switches to run trains - thus the automatic reverser units to do it for you. You could even do just liek DC and have the polrity flipped ont he main side of the tracks instead of the loop, but this means you need an autoreverse that can handle the full load of your layout - kind of silly when you can flip just the section with a train on it so all it has to deal with is the load of one train.
–Randy
Thanks for the help.
If you’re talking DCC, here’s a link to Wiring For DCC. Check out the sections on reverse loops – it sure helps when there’s diagrams!