Can someone check this wiring?

John,

I think you're good as long as you remember one thing.  Before you close either switch in preparation for moving a train from one loop to the other, you need to make sure that both transformers are set to approximately the same voltage.  If you don't they will fight each other, leading to potentially large current flowing -- enough to trip a breaker.  Once they are equal you can then close one or both switches.  The transformers must remain set the same until the entire train is through the crossover, particularly if it's a passenger train with lighted cars.

Once the train is through the crossover you can open both switches up and resume setting the transformers separately to any setting you prefer.

The process is exactly the same when the train is coming back to the original loop.

BTW - 'Hot' and 'Common' were good choices on your part to describe the transformer connections, particularly Common.  Many people are tempted to call it 'Ground' instead, which can lead to confusion if you use DC to power accessories.  I like to reinforce the fact, when we're using AC , that it is AC and it is special as a result.

Mike

Thanks for the tip Mike.

Actually I was planning on unplugging the other transformer when using a single transformer for the entire layout.

To run one train on both loops from either transformer:

1.  Unplug the transformer not being used

2.  Close the two toggle switches between the loops

3.  Turn on remaining transformer power

Is that method sound?

John

Yep.  That will work, although you might find that the prongs on the wall plug of the unplugged transformer may have a significant voltage between them if the throttle on that transformer is left at a high setting before you unplug it.  This is because it's still connected to the track, which is now powered by the other transformer.

M.H.M.

Thanks Mike

John

Another option, that I use, is to use SPDT center OFF switches, one per block ( one per loop in this case ).  Where you have SPST switches, I have isolation track sections to separate the blocks/loops.  The center SPDT terminal goes to track, each of the other terminals connects to one transformer and the same terminal of the additional SPDT switch(es), in parallel.  This arrangement works out as a selector array where any track block/loop can be powered from either transformer, but not both transformers at the same time.

I can draw a diagram  if interested.

Hi Steve,

I want to be able to run two trains from their respective transformers at the same time (in isolated loops) or either one to run a single train on the entire layout.  The SPST will go to an 1 3/8" Fastrack section with the jumper removed to isolate the sections.

John

Undersood.  Selectors as described will do all that, and more.

@SteveH posted:

Undersood.  Selectors as described will do all that, and more.

Maybe the diagram would help Steve if you get a chance.  "but not both transformers at the same time." threw me off

Thanks,

John

With this arrangement only one transformer at a time would be connected to either or both tracks.  The other transformer can be simultaneously connected to another track(s).  Both transformers won't be directly hardwired together.  Only the train would do that.

Maybe this will clear it up.

Another way of thinking about this is eack loop gets to choose either power source.

OK.  The SPDT are for the transformers.  The crossovers still get a SPST at the isolation track.  Transformers can remain plugged in.   That seems better than what I was going to do.

Thanks Steve

John

You dont need SPST switches between loops.  In my diagram, those are isolated sections between crossover turnouts.

OK.  Jumper removed and left as is.

Are there any issues when the train crosses over?

John

Like Mike described, transformer output voltages should still be closely matched and phased.

Got it.

Thanks as always.

John

In discussions like this please do not use “Reply with Quote” just to repeat the pervious post! It is not necessary and really clutters up the thread.

@Rich Melvin posted:

In discussions like this please do not use “Reply with Quote” just to repeat the pervious post! It is not necessary and really clutters up the thread.

Rich,

Thanks for reminding us of this but I've come to a need to disagree, hopefully respectfully.

Just a few days ago I followed your advice, which has been sound advice over the years I've been posting here, and replied to a post without using "Reply with Quote".  Not any more.

My post from a few days ago quickly became, not only irrelevant, but downright wrong and quite foolish-looking because the OP edited the post I was commenting on, and changed the nature of it significantly, this being done after I had posted my response.

It's true that I could have changed mine as well in response, but I'm sure that many folks had already see it by the time I noticed the OP's change.

There's only one good way not to stick your foot in your mouth by accident, without being able to predict the future.  In light of the ability for previous posts to be edited, at any time, by their owners, it's important to include a copy of the original post as it appeared when the response to it was generated.

However, an alternative might be saving a copy of the pre-edited post off line, in case it's significantly changed later on.

Mike

@Mellow Hudson Mike posted:

My post from a few days ago quickly became, not only irrelevant, but downright wrong and quite foolish-looking because the OP edited the post I was commenting on, and changed the nature of it significantly, this being done after I had posted my response.......................

Mike

I often try to modify the quote (like I just did) for the very reason Rich stated.   But I respectfully agree with Mike that communication can suffer without at least part of the quotes or some sort of context in the responses.

John