# Connecting Inner & Outer Loop



## nrandel (Jan 6, 2012)

Our clubs Lionel layout has an outer loop and an inner loop. We use O-gauge tubular track. Recently four turnouts were purchased so we could run a train from the outer and inner loop. A pair of turnouts are hooked together with isolating pins on all three rails between the turnouts. There is a pair of turnouts to go into the inner loop and a pair of turnouts to come out of the inner loop onto the outer loop. There are two transformers (CW40 or 80). One for each loop. Their power cords are coming off the same outlet. The engine switch is in the forward only position.

The problem is when the engine crosses over onto the other turnout, the engine stops and the transformers indicate a short (green light on both transformers are blinking). Is there anyway I can do this?


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## T-Man (May 16, 2008)

The red terminal attaches to the center rail for both transformers. The engine shorts it out when it connects them momentarily. Maybe?


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## Dave Sams (Nov 24, 2010)

Where my 3 loops connect, I only isolate the center rail and the derailing rail. The outer rail is connected on all loops.

I have gone from one loop to the other using 2 transformers, but usually I energize both loops (actually blocks) with the same transformer. I have an extensive system of single pole double throw switches for my blocks. 

Make sure your transformers are in phase.

Phasing and double throw switches are mentioned elsewhere.

Do you have the same kind of switches on other sections of the layout? Do all locos have the same problem? Some of my locos short out on my 1122E's. Either the uncoupler or part of the frame under the coupler hits the center rail. In either case, a piece of electrical tape solves the issue.


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## BigAl56 (Dec 14, 2011)

Your transformers are probably out of phase. Unplug one of the transformers and turn the plug around 180 degrees then plug it back in. That should fix the problem.


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## gunrunnerjohn (Nov 10, 2010)

Yep, top suspect is phasing. Note that you're also pushing the full current through the pickups of the locomotive crossing the boundary, if you do that a few more times you're liable to melt some wiring insulation inside the locomotive!


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## Cape T/A (Aug 15, 2012)

Would it also cause a problem if the engine has 2 pick up points and one is on the outer loop while the other is on the inner loop?


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## gunrunnerjohn (Nov 10, 2010)

If there are widely different voltages, you sometimes get a spark, but usually if the transformers are phased properly, you get minimal current flow even if the voltages are a bit different.


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## tjcruiser (Jan 10, 2010)

Catching up to the thread on my end, but my first thought was phasing, too, as you guys duly noted, above. Flig a plug!!!


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## BigAl56 (Dec 14, 2011)

> Would it also cause a problem if the engine has 2 pick up points and one is on the outer loop while the other is on the inner loop?


Yes. If the transformers are out of phase that would create a dead short and probably melt wiring inside the engine.


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## Cape T/A (Aug 15, 2012)

But if the transformers phases are the same would it cause a problem?


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## gunrunnerjohn (Nov 10, 2010)

If the transformers are phased properly, it's not a major issue. As long as the two transformers powering the loops are not set to widely different voltages, there will be minimal current flowing between them. This is a normal happening with multiple power districts when transitioning between them.


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## BigAl56 (Dec 14, 2011)

Phasing transformers allows you to cross between them without damaging and shorting out the layout and trains.

Here is a test. With the power OFF You want to connect the outside rail terminals of both transformers together. U to U in most cases. Then you want to touch the center rail terminals together. A to A in most cases. SLOWLY turn up the power on the transformers. If the transformer vibrates and makes sounds like it is internally hemorrhaging STOP. Reverse ONE of the plugs and try again. Once you can tie two transformers together and crank up the power without burning down your train room you are ready to go. Mark your plugs so you will know how to orient them in the future. Leave the common outside rail returns, U connections, tied together and reconnect to the layout. Now your equipment should be able to cross freely from one transformer to another.


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## nrandel (Jan 6, 2012)

Gentlemen, it can't be a phase problem because both cabs are plugged into the same outlet and let's not forget that equipment with floating grounds have polarized plugs meaning they can go in the outlet only one way. What I haven't tried is to tie the cabs neutral terminals together so the inner and outer loops are on a common neutral. I also need to put a ground checker on the outlet just to make sure it was hooked up correctly. Thanks guys for giving me some ideas.


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## sjm9911 (Dec 20, 2012)

I would still check the phasing in case a power cord was replaced. Are the lockons on the correct rails ( would it make a difference? ), power to center rail , outside or inside to ground the same on both loops? Was another engine tried to rule out a problem with the engine. Dave might have a point in using only 2 insulators, maybe its trigger ing the non derailing feature of the switch. Just throwing out ideas. They may or may not help.


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## gunrunnerjohn (Nov 10, 2010)

Lionel has had several incidents where the phasing of their bricks were incorrect for parts of the production run, check the phasing!

I have two PowerHouse 180 transformers powering two loops with break at the crossover switches, works like a champ with no issues. Yes, it's phased properly.


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## BigAl56 (Dec 14, 2011)

Sorry, I went back and looked at your original post and these are modern transformers you are using. So you are correct they should be phased by their polarized plugs. That being said, you never know with those factories in China. Run a phase test as I described above to be sure.


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## gunrunnerjohn (Nov 10, 2010)

For the PowerHouse 180 specifically, there were issues with phasing before a certain date code, I believe it was around 2000. Also, some CW-80 transformers were wired backwards on the secondary, that would probably cause a problem as well.

It's cheap and easy to check phasing, so there's no reason not to do it and eliminate it as a possibility.


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## nrandel (Jan 6, 2012)

*Replies to questions*



sjm9911 said:


> I would still check the phasing in case a power cord was replaced. Are the lockons on the correct rails ( would it make a difference? ), power to center rail , outside or inside to ground the same on both loops? Was another engine tried to rule out a problem with the engine. Dave might have a point in using only 2 insulators, maybe its trigger ing the non derailing feature of the switch. Just throwing out ideas. They may or may not help.


The feeders are correct and other engines short out the cabs. The two loops are blocked with insulators - all three rails.


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## gunrunnerjohn (Nov 10, 2010)

Just a thought. If you refuse to even consider the suggestions here, I'm not sure what help we can give. The process of debugging is the process of elimination. You eliminate a possibility and move on. We seem to be stuck on eliminating one of the most common possibilities.


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## nrandel (Jan 6, 2012)

*Reply*



gunrunnerjohn said:


> For the PowerHouse 180 specifically, there were issues with phasing before a certain date code, I believe it was around 2000. Also, some CW-80 transformers were wired backwards on the secondary, that would probably cause a problem as well.
> 
> It's cheap and easy to check phasing, so there's no reason not to do it and eliminate it as a possibility.


The cabs are the CW-80's. I will check the phasing tomorrow night and will keep you posted.


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## nrandel (Jan 6, 2012)

areizman said:


> Phasing transformers allows you to cross between them without damaging and shorting out the layout and trains.
> 
> Here is a test. With the power OFF You want to connect the outside rail terminals of both transformers together. U to U in most cases. Then you want to touch the center rail terminals together. A to A in most cases. SLOWLY turn up the power on the transformers. If the transformer vibrates and makes sounds like it is internally hemorrhaging STOP. Reverse ONE of the plugs and try again. Once you can tie two transformers together and crank up the power without burning down your train room you are ready to go. Mark your plugs so you will know how to orient them in the future. Leave the common outside rail returns, U connections, tied together and reconnect to the layout. Now your equipment should be able to cross freely from one transformer to another.


 We sure wouldn't want to burn down the place because we're located in the basement of the Virginia Museum of Transportation.


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## gunrunnerjohn (Nov 10, 2010)

The typical installation only isolates the center rails, the outside rails are normally common throughout a layout. If you run TMCC/Legacy, this is really mandatory.


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## gunrunnerjohn (Nov 10, 2010)

In reviewing the thread, I have another thought. Electronically controlled transformers tend to get testy when you connect their inputs together. I'll bet, assuming phasing is correct, that a couple of PW transformers like the 1033 or similar, would solve this problem on the spot.


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## servoguy (Jul 10, 2010)

What you are doing with two transformers is not recommended. What is better is to be able to switch both loops to one transformer using a single pole, double throw switch. 

Also, for all you guys unfamiliar with 022 switch non-derailing operation, each switch has two plastic pins, one in the straight path and one in the divergent path. When you mate two switches together, you will have the outside rails totally isolated due to having plastic pins in both outside rails, and if you want to isolate the two sections at the switch junction, the center pin will also be plastic. So a jumper needs to be added between the outside rails of both sections to connect the outside rails together. 

If you use the SPDT (single pole, double throw) switch to switch the power to the center rail, you do not have to be concerned about the phasing, but I believe it is good practice to have the transformers phased the same. It can prevent problems if there are mistakes during operation.


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## gunrunnerjohn (Nov 10, 2010)

Bruce, for command control, your solution is simply not a solution. You need continuous power, and having a switch for every transition isn't going to work. You could have multiple locomotives on each of the power districts. Having multiple transformers powering independent power districts is a fact of life, and works very well I might add. For both Legacy and DCS, the transition between similar transformer voltages is seamless and you don't even see it. Even with the ZW-C powering independent power districts, no problems arise in normal operation.


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## servoguy (Jul 10, 2010)

I was assuming we were talking about conventional operation here. Did I miss something?


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## gunrunnerjohn (Nov 10, 2010)

I don't know. However, for conventional or command, there should be no reason to have issues transitioning blocks with separate transformers, countless layouts do it successfully.


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## BigAl56 (Dec 14, 2011)

> The two loops are blocked with insulators - all three rails.


Once you have tested and verified the phasing remove all insulators on the outer rails except where switches require them. The outer rail should be common to the entire layout.


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## nrandel (Jan 6, 2012)

Last week at a run meet I took a wire and went from black to black terminal on the cabs. Then I took another wire and went from the red terminal on one cab and touched the red terminal on the other cab and it shorted out both cabs - the green light was blinking. What's my next step.


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## BigAl56 (Dec 14, 2011)

Could be a reverse wired transformer. Since the plugs are polarized try connecting black to red and visa versa. If that works try filing down one of the wider plug leads and reversing it. Then try red to red black to black again.


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## servoguy (Jul 10, 2010)

I would use a meter rather than cut and try. Much safer for the equipment.

Did you have the output voltages of both transformers the same?


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