3 loops (isolated with fiber pins) - Power supply options?

[lionelsoni]

Actually, far from proposing that you run three trains with one transformer, I'm recommending that you not run one train from two transformers, which is what will happen as you move from a loop powered by one transformer to a loop powered by another transformer.  If you really propose to isolate all three rails at the crossovers, then, in addition to the undesirable fault-current and voltage-spike effects that you read about in the posts I referred you to, you run the additional risk of burning out the knuckle springs of metal couplers.

The reason I asked about concentric loops is that they facilitate a pretty simple solution to all these problems.  Power the middle loop from one transformer.  But power each of the other loops through a single-pole-double-throw (SPDT) switch that can connect its center rail either to that loop's own transformer or to the middle loop's transformer.  That way, before moving a train between the middle loop and one of the other loops, you can join that other loop to the middle loop and run the train safely over the crossover entirely under the control of the middle loop's transformer.

In any case, do not isolate the outside rails between loops, only the center rail.

[lionel2986]

 Hello,

They are concentric loops. The outside loop must go through the middle loop to get to the inside loop.

I don't think one of the transformers I mentioned could power 3 loops with atleast 3 engines.

[lionelsoni]

Don't run between loops powered by different transformer outputs.  Search "fault current" for explanations and simple alternate ways to wire your layout.

Will it be possible to move directly from any loop to any other?  Or will they be effectively concentric, that is, have a connection between loops A and B, and between B and C, but not between A and C?  If the latter, there is a very simple and safe alternative.

[lionel2986]

 Hello everyone,

My layout is fairly simple in that it will have 3 loops, but it will allow for trains to switch from one loop to another via 022 switches. I have mostly 0-27 engines with can motors. I also have a few transformers from starter sets (I could use one to power the 022 switches and the accessories and lights). Then I have two "MRC Tech II Trainpower 027 Solid State AC" transformers. I am not sure of their wattage, but they seem to feel best powering my layouts of the past. The specs on the box read:

Input 120VAC 60HZ
Output 0-17VAC Variable/18VAC Fixed
Total Output 40VA

I also have a few Lionel AC1803000 and the specs are

I/P: 120 VAC-60HZ
77W.

O/P: 18VAC
3A

 

Is it possible to power the outer two loops with two MRC Tech II, and the inner loop on a the AC1803000? I am on a tight budget and have too many of these starter set transformers I don't want to see go to waste. I figure if I dedicate one to lights and accessories, the ones powering trains will experience less load.