Isolating an inner loop with two power supplies

(1) insulating pins inserted in the center rail between all switches connecting the two loops.

(2) Ensure that the two transformers are in-phase, insofar as the AC current coming out of them. Otherwise, any locomotive crossing the insulated section will cause a short circuit.

Phasing is accomplished by setting the two transformers to the same output voltage, connecting their return leads (the ones going to the outer rails) and then touching the other wires together. If there's no spark, you are good to go. If you get a spark, reverse the wall plug on one of the transformers and repeat the test. This time there should be no spark.

---PCJ

@RailRide posted:

(1) insulating pins inserted in the center rail between all switches connecting the two loops.

(2) Ensure that the two transformers are in-phase, insofar as the AC current coming out of them. Otherwise, any locomotive crossing the insulated section will cause a short circuit.

Phasing is accomplished by setting the two transformers to the same output voltage, connecting their return leads (the ones going to the outer rails) and then touching the other wires together. If there's no spark, you are good to go. If you get a spark, reverse the wall plug on one of the transformers and repeat the test. This time there should be no spark.

---PCJ

PCJ is right on track.  Both good suggestions.  There's one additional one that I'd like to recommend though, after the above are in place and functioning:

(3) Make sure that the throttle positions on the two transformers are about the same as your train transitions from one loop to the other.

If you don't do this your train will jolt, either slowing dramatically or speeding up suddenly as it crosses a joint with an insulating pin in it in going from one loop to the other.

Mike

@Mellow Hudson Mike posted:

PCJ is right on track.  Both good suggestions.  There's one additional one that I'd like to recommend though, after the above are in place and functioning:

(3) Make sure that the throttle positions on the two transformers are about the same as your train transitions from one loop to the other.

If you don't do this your train will jolt, either slowing dramatically or speeding up suddenly as it crosses a joint with an insulating pin in it in going from one loop to the other.

Mike

Hi Mike

Ok, so I followed your advice and PCJ's and tested the power supplies for phase.  I had to file the plug on one of the power supplies in order to be able to flip the plug around.  tested for spark again and got no spark or flashing green lights on the power supplies.  I run an engine through the switch and I get a short.  I tried this a few times with an engine that had 8 wheel drivers and pickups under the drivers, none on the tender.  I tried a doodlebug which has two sets of four wheels each with their own pick ups.  I was able to get this to work but I'm not sure why this behavior with the other engine.  I just noticed there are insulators on the outside rails of the Fastrack switches I'm using could that be affecting things?

Thanks

Roger

1. Are you sure the short is caused by an electrical issue and not a physical issue, such as the engine derailing as it goes through the switches ?

2. You shouldn't need insulators on the outside rails of the Fastrack. The only rail that needs to be isolated is the center rail as you transition from one loop to the other. I would remove the outside rail insulators.

3. Since you are using Fastrack, the easiest solution is to put a 1 3/8" "fitter" piece of Fastrack between the two switches. This piece already has the center rail cut. There is a small wire on the underside which connects one end of the piece to the other end which bypasses the center rail cut. Remove this wire and you should be good to go.

4. You could also just cut the center rail with a Dremel and cut-off wheel and accomplish the same thing.

5. As others have said, just make sure that the voltage is about the same between the two loops when you do the crossover.