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Reply to "Wiring: Star, Home Run & Bus"

Jim C:  I don't think Russell is trying to distinguish between the outside rail and the inside rail as I read your comment. Russell is following the norm in my opinion as referring to the two outer rails as "outside rail." It does not matter whether it is inner or outer. After all, on a straight spur, which is outside and which is inside?
 
He is merely differentiating between the "center rail" and the "outside rails." In fact, both ouside rails should be at about the same potential (talking 3-rail layouts here) everywhere with the exception of the short segments on switch turnouts that are insulated in order to provide non-derailing automatic switching. TMCC ultimately uses both outside rails on most layouts. They (the outer rails) are typically tied together at every bumper and by almost every axle set -- I say almost, because there are a very few out there with plastic wheels or with insulated bearings for 2-rail operation.
 
In fact, I will really open a can of worms in my next post.
 
Originally Posted by F&G RY:
Originally Posted by Russell:

Per Barry, The most dedicated DCS guy there is:

A Single loop can have one power connection.

Optimally, you will break the center rail at the opposite point of the loop from the Power Drop. But even this is not absolutely required.

Proof? I did that on my 11' x 23' figure 8 layout and it worked fine except on the stub sidings. They were functional but didn't have 9 or 10 signal readings.

It now has 2 power drops at opposite ends simply because I was popping the circuit breaker with my Big Boy Smoking and pulling 53 cars when It got to the far end. A second power drop fixed that. And I still have no breaks in the center rail.

Admittedly, I've added more stub sidings and my signal sucks in a couple spots, but I can run the train right through that 3 foot spot and get control back as it crosses the switch after it.

Same Length to each drop?

Per Barry here on the forum several times, NOT AT ALL, Run wire pairs of Hot and common to each drop, whatever length is needed.

 

Per Barry, you don't need to break the outer rails at all, just the center rail.

Signal goes TIU to engine and Back on Center rail, Outer rail is just a common for it to reference against.

Besides, If you want TMCC or Legacy to work well, a continuous circuit on the outer rail is best.

Russell reread page 16 of Barrys' book bottom of page about what rails do what.

TMCC and Legacy reference earth ground. The common in these does not have to be the outside rail. How does it know the difference inside or outside.

 

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