Bus or Star Wiring?

I started out with DCS and added Legacy a year or so later. I wired my layout for DCS using the 'star wiring' method. After doing that, I think I actually prefer the 'star wiring' method. To me, it just seems more organized, easier to keep track of your track wiring, easier to troubleshoot, easier to switch power on-off to a block, etc. And you never know, you might just end up wanting to add a DCS system someday. If I had it to do over again, I would wire it the same way. I'm sure there are pros and cons for each method, but I like the star method.

One more thing about wiring that I learned from my mistakes. Which ever method you choose, figure out your wiring plan and make a wiring diagram before you start. Changes will be made as you go along wiring things, just be sure to document any changes you make as they are made. I didn't do this, thinking no big deal, I'll just document it all when finished. Upon completion, a few things had been forgotten when I went to update my wiring diagram, not good.

Also, using different color wires for different things can help to identify things later on. I would have this all planned out before starting anything and again document changes as they are made. Wire is kind of expensive and quantities of several different colors could add up. It might be less expensive to have larger spools of only a couple of wire colors. In that case electrical tape is available in quite a few colors ($3-$4 per roll) and you can also use that color code the wires. Then there are wire labels and labelers made just for wire labels. Labelers could also be used to ID many things other than just the wires.

I just watched a MrMuffinsTrains  video that explained the 2 types of wiring very well.   I learned something !    It was in his newsletter email of 8 Jan 2020., check it out !

I’m with RT12, highly recommend star wiring. It provides better power to all the track, close and far from the transformers. I use Lionel’s Legacy Control System, however, if I choose to add the MTH DCS System, the wirings in place. I also recommend different color wiring for accessories, for Turnouts, etc. I really agree on a diagram, which I didn’t do for future thoughts. This helps to pin point situations down the road. Good luck, place pictures of your layout on the forum when possible. Happy Railroading 

There is a third option that combines the two. (Let the flames begin!) On my last layout, I ran buss wire for the commons and star for the hots. I ran a 12 gauge white common wire around the layout connected to electrical buss bars to connect feeders. I ran star wiring to the center of each loop for the hots and feeders from a terminal strip there. I never had a DCS issue.

George

I agree with George above. It was RJR that pointed this out to me a while back (I don't always see the obvious). Actually, even with star wiring, all your common rails are tied together and form a bus. They are not isolated like the center rail. Even though I used a pair of wires (hot & common) to each one of my blocks, the common rails still form a common bus and it all works just fine. I just don't have the separate, specific common bus wire as George describes. IMO, the method George describes above should be just fine. 

FWIW my home layout is star wired. Our club modular layout is bus wired. Both have DCS and TMCC. Both run. 

With all of those stub sidings, I would urge you to wire them so you can turn the power off. The modular layout has an 8 stub track yard that measures ~20' long. When the yard is powered we have serious signal strength problems on the 20x40 mainlines (2). With the yard setup dead-rail, we're seeing signal strength of 10 everywhere.

This is probably a dumb question but what is loop wiring and star wiring and what are the differences?  I always wire my track up to switches for block sections. 

Star wiring starts at a single point and runs to each connection from there, Buss wiring shares a common wire running the length of the track and it follows the layout and connects every so often, with only one or just a couple of connections to main power.

HustleMuscle400 posted:

I'm finally at the wiring stage of my layout and I'm not sure whether to go with bus or star pattern wiring. the layout is pretty big at 8'x24'10" and I'll be using both Lionel Legacy and MTH TMCC. Any input would be greatly appreciated!

Thank You!

Have you purchased Barry’s 3rd edition?  Read it.  Also, use the search function here in he forum to unlock a treasure trove of more info than you will need.  Probably more pages than “soldering wire to rail” or “do I use flex-bed”.  Buss is easier, star takes more wire, work and time.  But, it only hurts once👍.  Good luck with whatever you do.

There's been a long debate of Buss vs. Star wiring. Lost in the discussion is the real culprit -- signal feedback. The key thing to remember is that there should NEVER be more than one feed in a block as the signal will interfere with itself between the feeds. Also, the feeds should be at one end of the block rather than in the center due to "bounce-back" from the ends (you only get a bounce-back from one end reducing signal loss). Ironically, even though the protocols are different, DCC wiring practices seem to work well with DCS, including "sbubbers" at the ends of a buss. The snubbers (also referred to as "Deats Filters" for Susan Deats' son) neutralize the signal when it reaches the end of the buss to prevent bounce-back.

If you're using insulated rail to trigger block or grade crossing signals, put .1uF capacitors across the gaps in the trigger rails to preserve the TMCC signal.

If you want to run a buss, DO NOT "LOOP" it (tie the ends together).

AGHRMatt posted:

There's been a long debate of Buss vs. Star wiring. Lost in the discussion is the real culprit -- signal feedback. The key thing to remember is that there should NEVER be more than one feed in a block as the signal will interfere with itself between the feeds. Also, the feeds should be at one end of the block rather than in the center due to "bounce-back" from the ends (you only get a bounce-back from one end reducing signal loss). Ironically, even though the protocols are different, DCC wiring practices seem to work well with DCS, including "sbubbers" at the ends of a buss. The snubbers (also referred to as "Deats Filters" for Susan Deats' son) neutralize the signal when it reaches the end of the buss to prevent bounce-back.

If you're using insulated rail to trigger block or grade crossing signals, put .1uF capacitors across the gaps in the trigger rails to preserve the TMCC signal.

If you want to run a buss, DO NOT "LOOP" it (tie the ends together).

 

I don't plan on using blocks on the loops of track so I shouldn't have to worry about any signal/power loss or bounce back.  I do however plan on isolating all the industrial stub tracks including the yard so I have the option to turn them off when not in use. My initial plan was to run a bus around the layout to power everything except the turntable bridge track and whisker track, but then I read about star wiring and i want to be able to run both Lionel and MTH trains smoothly so naturally the internal debate began and well... here I am lol.

Good morning all

I could use some advise. I have written on other boards and have received great information as I am somewhat electrically challenged.  

About my layout:

8 X12, all fastrack

3 separate parallel loops. (subway layout)

currently 6 manual 036 switches, more to be added later.

currently using a Z4000 and added DSC.

From all that I read, star wiring is the method to use to support DCS signals. I have three (3) terminal blocks, (MTH 50-1014).  At this time I have the  Z4000 connected the TIU; TIU out to the terminal track and the hot and ground from the track to the terminal block.

I was planning on three blocks, one for each track, to maintain signal integrity. If I read details about star wiring correctly, I would run a positive and ground wire from the terminal block (50-1014) to a terminal @10 ft away. 

Again if I understand the wiring, I would drop wires from the track to the terminal , positive and ground. I would do this for each of the three loops.

If I make all the connections properly, with proper connectors etc., I should have no issues with power to all three loops and a "good" DCS signal. I already have the wires in place and made the drops . Next step is to hook them up. 

Based on this , is there anything else I need to do?  Also is there anything about what I planned incorrect? 

Thank you all in advance for your feedback !

It would be pretty much unpossible to use a star wiring pattern on the Plywood Empire Route:

I ran two #10 buss wires with power drops to the track about every four feet. Third #16 buss provides power to accessories and track switch motors. I run DCS with a Remote Commander and it all works.

@Steven posted:

Good morning all

I could use some advise. I have written on other boards and have received great information as I am somewhat electrically challenged.  

About my layout:

8 X12, all fastrack

3 separate parallel loops. (subway layout)

currently 6 manual 036 switches, more to be added later.

currently using a Z4000 and added DSC.

From all that I read, star wiring is the method to use to support DCS signals. I have three (3) terminal blocks, (MTH 50-1014).  At this time I have the  Z4000 connected the TIU; TIU out to the terminal track and the hot and ground from the track to the terminal block.

I was planning on three blocks, one for each track, to maintain signal integrity. If I read details about star wiring correctly, I would run a positive and ground wire from the terminal block (50-1014) to a terminal @10 ft away. 

Again if I understand the wiring, I would drop wires from the track to the terminal , positive and ground. I would do this for each of the three loops.

If I make all the connections properly, with proper connectors etc., I should have no issues with power to all three loops and a "good" DCS signal. I already have the wires in place and made the drops . Next step is to hook them up. 

Based on this , is there anything else I need to do?  Also is there anything about what I planned incorrect? 

 

Thank you all in advance for your feedback !

 

Doesn't sound exactly right to me and not sure what you mean by, "TIU out to the terminal track and the hot and ground from the track to the terminal block."

One method would be this:

The Z-4000 has two output handles. Output 1 would be run into the TIU (fixed 1, presumably) and then fixed 1 out to the pos/neg terminals of the first MTH terminal block. That MTH block would be designated for loop 1 and you would run as many drops as you need from that MTH block all around loop 1 to the trackage to insure good voltage to all sections of the loop 1 track. My method is to use a two gang terminal block (available from most electrical supply houses, like Del City) for each drop on each loop. I screw the small terminal block to the layout underneath where that drop is going to go. I then connect the pos/neg wires from the MTH terminal block to one side of the terminal and drop 16 gauge wires from the track above through the layout to connect to the other side of the small terminal block. It's not mandatory that you do it like this, but I find it easier to make the track connections this way. I use 14 gauge wire from the MTH block to the small terminal. Obviously, you may end with 10-15  two gang terminal blocks for all three of your loops.

Then take Output 2 of the Z-4000 and split/splice it in two, so you have two pos and two neg wires. Run one set of wires to fixed 2 of the TIU and out to the second MTH terminal block for loop 2 only and run as many drops as you need from that MTH block all around loop 2 to the trackage to insure good voltage to all sections of the loop 2 track, as outlined above.

Take the second pair of wires from Output 2 of the Z-4000 and run them to Variable 1 of the TIU (I would first convert Variable 1 to a fixed output first) and then out from the TIU to the third MTH terminal block for loop 3 and run as many drops as you need from MTH terminal block 3 all around loop 3 to the trackage to insure good voltage to all sections of the loop 3 track.

Running three separate loops with only two transformer outputs is always challenging. Considering that the two loops off one handle of the Z will have the same voltage applied, you may want to mix and match the above for your loop's configurations and usage. You could also consider adding another transformer - maybe a Z-1000 - to run one of the loops independently from the Z-4000. 

You may also need to separate your tracks into blocks, but I would try this way first and if you have operational issues with your MTH equipment, you can address that later.

Could someone please provide a simple sketch of what is being discussed here, as its gotten quite confusing to follow the recommendations? 

Thanks!

If you are serious about using DCS, Barry's book has all of this explained and pictured very well.

I have a fairly good sized around the room layout and bit the bullet to run a pair of wires to each of the block ends.  Yes it did take a lot of wire and now that it is almost done I am switching to battery R/C.

For what it is worth I found the most economical way to purchase wire was at our local contractor's supply house.

Years ago I purchased cut colors from HD but the cut prices of 100' of wire was creeping close to the price of a 500' wholesale roll, it did not make sense to do otherwise.

I too use 12 colors of wire, twelve colors of tape, numerical wire labels and alpha wire labels.  I have had to trouble shoot problems and it was a quick process.

Here is a peek under the hood:

Who is Barry, what is the title of his book, & who is the publisher ?

Maybe a good industry for an o-gauge layout would Buss & Starr Electrical Supply !!!

The late Barry Broskowitz wrote The DCS Companion to aid all DCS users. He also was a frequent advisor to confused and frustrated DCS users on this forum; his posts remain archived here.
ISBN:1517374391 for the latest (third) edition.

First, thank you all for the feedback and details for the wiring.

Richie, I poorly explained what I did as far as wiring. I did wire properly as I am operating trains with DCS on one track.

The issues I am experiencing (and yes electrical novice here) is :

1. adding the additional tracks

2. terminal  blocks at the other portions of the layout. This is where I am challenged.  Do I connect the wires ,positive on one side and ground on the other for both the wires dropped from tracks and star wire? Or on the same side?  I have tried and still  experiencing circuit breaker pops. I am not sure where I am going wrong. 

Barry's book has been very helpful but again being  a novice still not getting there.

Here is a simple diagram of my layout

Once again thank you all !  

@AGHRMatt posted:

There's been a long debate of Buss vs. Star wiring. Lost in the discussion is the real culprit -- signal feedback. The key thing to remember is that there should NEVER be more than one feed in a block as the signal will interfere with itself between the feeds. Also, the feeds should be at one end of the block rather than in the center due to "bounce-back" from the ends (you only get a bounce-back from one end reducing signal loss). Ironically, even though the protocols are different, DCC wiring practices seem to work well with DCS, including "sbubbers" at the ends of a buss. The snubbers (also referred to as "Deats Filters" for Susan Deats' son) neutralize the signal when it reaches the end of the buss to prevent bounce-back.

If you're using insulated rail to trigger block or grade crossing signals, put .1uF capacitors across the gaps in the trigger rails to preserve the TMCC signal.

If you want to run a buss, DO NOT "LOOP" it (tie the ends together).

 

Excellent advice, Matt!  One thing:

"If you're using insulated rail to trigger block or grade crossing signals, put .1uF capacitors across the gaps in the trigger rails to preserve the TMCC signal."

I tend to use 1 specific outside rail for ground & TMCC signal.  The other (in the appropriate places) is reserved for use as an insulated rail to trigger signals.  I don't use the .1uF capacitors.

George

I'm not sure I can explain it any better and hopefully you are not confusing terminal blocks with track blocks. Track blocks are simply a method of separating a loop, in your case, into two or more electrified sections of trackage in that loop by, essentially, cutting the center rail on either side of a power drop so that section of trackage is only fed by the power drop in the middle of that "track block" and does not transfer pos. electricity to the sections of trackage on either side of it. However, we are not talking about "track blocks" here.

A "terminal block" is simply a base of material, like plastic, that has electrical terminals on either side of center. In the case of the MTH terminal block, it has an incoming pos & neg feed from the TIU and 12-24 outgoing pos & neg terminals that connect to your track. Since the MTH block has 12-24 output terminals, you can run multiple power drops from that MTH block to several connection points on the loop that MTH block services. You can connect the wires from the MTH block to the track at several different locations to insure good power to all parts of your loop either directly (solder) or use small connectors (Fastrack) or indirectly to a smaller, 2 gang terminal block and then drop wires from your track to the opposite side of that small terminal block.

You always want to connect pos to pos and neg to neg. 

Here's a poor diagram of your layout - this assumes you want to be able to run DCS on the outside loop. If not, as shown on your diagram, jus bypass the TIU and connect the Z-1000 to MTH block 3 and then out to the track. Each small blue square is a small, two-gang terminal block. It also assumes you need 4 power drops per loop. It also shows only one wire coming out from each MTH block, but that is a pos/neg pair to the small block and a pos/neg pair from the track to the small block.

Hope this helps.  

Here's another poor diagram just showing the connections on one loop from the MTH block for that loop to the small two-gang terminal blocks and to the track. I only show 3 small blocks instead of 4, for "clarity" purposes.

Again, you can skip the small, two-gang terminal blocks and just run your wires directly from the MTH block to the track at the same multiple locations if it makes it easier for you.

Found some pics, too. Note that the wires from the MTH block are not hooked up - only track to block. Also, TVS Suppressor is soldered in place.

Richie

You explained it very well and I understand. Thank you for the details and your patience. 

The one step I did not do is isolate the track blacks.  I am using Lionel Fastrack  so I will have to cut the center rail to isolate the track blocks. Your diagrams as most helpful !  I assume not isolating the train blocks is the reason for the shorts I have been experiencing.

thank you again ! 

Actually, that should not make a difference.

Track blocks can be helpful for things like helping to isolate electrical problems, but if you're not experiencing any DCS issues, I wouldn't bother. Lots of DCS layouts (like mine) run fine w/o separating the loop into track blocks.

The layout should run perfectly with or w/o track blocks, so something else is wrong. 

I would get back to basics and get one loop up and running first and once that is set, add the next loop and get that running and only then add the third loop.

Richie

thanks again. Will go basic. I’ll check the one loop I have running then move on to the next loop. I’ll set it up without train blocks And see what happens.

thanks you