I'm a visual person. While I've done a lot of reading on this, I can't get the picture in my mind what the difference is between these. Can someone post a drawing (hand drawn or otherwise) of what these would look like? Is home run and star the same thing? Thank you for your help!  Terry

Original Post

Yes. Homerun and star wiring are the same thing.  Picture it more like a clock with your TIU in the center pivot where the clock hands are mounted.  Power wires would run out and common wires would run back at (for example) 2:00, 4:00, 6:00, 8:00, 10:00, and 12:00 o'clock.  You would make a cut in the track at 1:00, 3:00, 5:00 etc. o'clock.

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Dennis

I'm retired. Now I work at being a pain in the butt.

Another way of saying it that worked for me:

a TIU Channel connected to a "hub" and from the hub "paired spokes" of hot and common going out to track. Just like a wagon wheel or air terminal hub. Another channel, another hub,=another power district/block.

 

A "hub" pictured below. A White [Common] and color-coded wire home-runned from a channel through the hub went out in pairs to the track.  Adapted to DCS on an existing  TMCC system and it worked pretty well.

100_1187-001

A&Y RY[NC's Southern/N&W connector].

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Dennis and Dewey. I see you on here a lot and Thank YOU very much for the info. It's making sense!

 

So using this star or hub pattern, the length of the runs should be as equal as possible at each point it connects to the track correct?

 

Thanks again, Terry

Terry,  Yes.  As close as possible to the same length.  Incidentally, this type of "star" wiring also works for TMCC (and I assume Legacy) so you can add the hardware if you want and run both without changing any wiring.

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Dennis

I'm retired. Now I work at being a pain in the butt.

Originally Posted by Dennis:

Terry,  Yes.  As close as possible to the same length.  Incidentally, this type of "star" wiring also works for TMCC (and I assume Legacy) so you can add the hardware if you want and run both without changing any wiring.

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Dennis

I believe this same length wire is nothing more than internet legend. I do not see any reason the wires to be the same length. Same length, either the pairs to the track or different length star connections.

 

 DCS sends a signal along the Hot to the engine and the engine answers via the common or vice verse. It travels 10 feet on the Hot gets to the engine and comes back on the common 10 feet and do what die. The point of the one drop per track segment is to avoid multiple paths of common and having the signal repeated.

Jim C

 

I interpreted Terry's question as "would", not "should".  I didn't mean to imply they had to be exactly equal.  Mine aren't, but for practical purposes to measure how much wire you need to buy, it would be prudent to do so.  Why wouldn't you anyway?  I can't see any reason why you would take a different route for each wire.  You don't have to buy paired wire either.  I bought my copper wire in 500 ft rolls at Home Depot and ran each hot and common separate but through the same benchwork holes together.

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Dennis

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I'm retired. Now I work at being a pain in the butt.

Originally Posted by F&G RY:
Originally Posted by Dennis:

Terry,  Yes.  As close as possible to the same length.  Incidentally, this type of "star" wiring also works for TMCC (and I assume Legacy) so you can add the hardware if you want and run both without changing any wiring.

.....

Dennis

I believe this same length wire is nothing more than internet legend. I do not see any reason the wires to be the same length. Same length, either the pairs to the track or different length star connections.

 

 DCS sends a signal along the Hot to the engine and the engine answers via the common or vice verse. It travels 10 feet on the Hot gets to the engine and comes back on the common 10 feet and do what die. The point of the one drop per track segment is to avoid multiple paths of common and having the signal repeated.

Does this mean that one loop (non-segmented) should only have one power feed from a TIU channel.  And would that mean there would be no reason in this case to even have a terminal block.

 

Mike

Not necessarily.  However, the thinking is you split at least the center rail between drops so you don't have to drops going to a continuous rail and creating a signal loop.  For a big loop, you'll want more than one power drop.

Originally Posted by gunrunnerjohn:

Not necessarily.  However, the thinking is you split at least the center rail between drops so you don't have to drops going to a continuous rail and creating a signal loop.  For a big loop, you'll want more than one power drop.

Thanks John, that helps.  What about the outer/ground, should that also be insulated so as not to confuse signals?

If you have a small loop and only 1 drop there is no need for a terminal block. Small would mean less than 10 track joints on the loop.

 

For a loop greater than 10 and smaller than 20 joints you would divide the loop into 2 equal segments with insulated rail joints on the center rail only. 2 Voltage drops would go halfway between the insulated pins. The voltage drops would connect to a terminal block and 1 wire would go to 1 TIU channel. If you ran each voltage drop wire into the TIU without a terminal block it would make no difference. The terminal block is there to make wiring easier.

 

The purpose of the insulated track block is to keep the engine from receiving multiple signals from the TIU.

Jim C

 

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.

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.

Jim C

 

OK what I'm reading is that all wires should be the same lengths for the star pattern? That's a serious waste of wire for some layouts. What I always thought was in regards to equal wire length means the hot and commons should equal each other in length. not all drops have to be equal.

 

Am I missing something? My trains run great with DCS and the star isn't equal at all but each hot and common is equal in length, never a problem.

ALL,

 

I very much appreciate your comments, pictures, drawings, etc.

 

Last night I got my DCS up and running without a hitch. Following Barry's book and a lot of your comments, it went without a hitch!

 

Thank you and this forum once again for providing so much great help! I am learning a lot!  Terry

 

I believe this same length wire is nothing more than internet legend. I do not see any reason the wires to be the same length. Same length, either the pairs to the track or different length star connections.

 

 DCS sends a signal along the Hot to the engine and the engine answers via the common or vice verse. It travels 10 feet on the Hot gets to the engine and comes back on the common 10 feet and do what die. The point of the one drop per track segment is to avoid multiple paths of common and having the signal repeated.

Marty W

You failed reading comprehension. Read my post about star wire length.

Jim C

 

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.

 

Bill

I really appreciate everyones comments on this. I have just finished setting up a temporary loop with DCS to give all this a shot. I spent a couple days looking at Barry's Companion Guide and the Rich's OGR video as well as all your comments.

 

Right now it's a loop with one dead end siding. After getting familiar with the DCS remote, I checked the signal strength everywhere and it's a 10. I have 1 terminal block for ease of wiring and used a lighted bumper on the siding.

 

As I'm learning from all this, it's what works for each of us and there are usually more ways than one to be successful. I am using the OGR shielded 16 gauge wire as recommended.

 

And again, I have benefited tremendously from your help. This forum continues to be a great place to learn and share. Thank you very, very much, Terry

Gentleman;

LocoMods has understood my poor description as intended. Outside rail is not center rail, inside or outside of loop does not matter to DCS.

And yes, it seems the DCS Companion states the engines reply on the outside rails.

I thought they spoke on the center rail because the outer rail does not need to be blocked but considering it more, the engine probably does not speak as often or as complex as the TIU and therefore the signals would not overlap as much.

 

EastonO;

You will find the numbers are always good on a small layout, the power is sufficient to overcome any issues. Problems creep in as you get complex and larger.

My 11 foot by 23 foot figure 8 with Wyes across the middle was great with 2 drops until I added an couple more dead end sidings.

I really need to break the center rail in a few places.

But since I'm replacing the whole thing with Scaletrax as soon as finances allow, It will wait. I only have one 3 foot stretch (across the top of a wye) where I can't command engines so I'm satisfied for now.

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