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Before I start, please let me give a HUGE kudos to Barry Broskowitz on his creation of the DCS O Gauge Companion. This book is absolutely invaluable. I have read, re-read and re-re-read this book and I still find something new and insightful every time I go through it. My hats off to you Barry!

Now...onto my questions. After building many temporary Christmas layout, I am finally building a permanent layout. I've decided long ago that I would use DCS on this layout. My layout is 12 x 18 feet and features several loops along with an upper level reversing loop (please see below).
Layout_12x18_v1_4_1
The vitals of the layout are:
1. Use DCS ( as stated earlier)
2. Use 4 postwar 275 watt ZW transformers with appropriate circuit breaker protection
3. Use 2 TIU's
4. Implement Track Block/Power Districts as recommended in the DCS O Gauge Companion. I chose this approach based on my experience with building Christmas layouts. I learned very quickly that ZW's can get hot quick when running a dual-motor passenger train that is pulling 6 - 8 lit cars! Track Blocks/Power Districts should remedy that problem pronto!5. All switches/accessories will be on their own dedicated ZW (not shown).

The goals of the layout are:
1. Be able to run multiple MTH, TMCC and Conventional engines
2. Run MTH/TMCC and Conventional engines at the same time but on DIFFERENT track loops
3. Be able to run Conventional engines on ANY track loop; not just on a dedicated track loop
4. Not tax any of the transformers.

As I was reading/reviewing the concept of Track Blocks/Power Districts, I thought it prudent to create a diagram of what the wiring for my layout would look like (please see below).
DCS Wiring Diagram
Using the recommended track block length of 5 - 6 track sections (50-to-60 inches) and given the size of the layout, I ended up with 54 Track Blocks assigned to 8 Power Districts (4 ZWs x 2 throttles per ZW). As you can see, I run the 4 ZWs into/through 2 TIUs; utilizing all TIU ports.

And that's when the following questions hit me!
1. If I'm using both the Fixed and Variable ports on the TIUs and one of my goals is to run Conventional engines on any track loop; how do I accommodate for that goal in the wiring? Would I need to acquire 2 more TIUs?
2. I read some where in the Companion that TIU Fixed ports could be changed to Variable ports but do not become true Variable ports; that a MTH add-on for MTH transformers only is required to make them variable by changing voltage at the transformer?
3. Am I over-engineering in regard to the number of Track Blocks? I understand why 5 - 6 track sections is optimal; given the frequency the TIUs use for communicating with the MTH engines. But if I double the track section count for the Track Blocks to 10 - 12 sections; might I be able to take advantage of frequency harmonics (for example high 'C' vs middle 'C' on a musical instrument)?
4. Or maybe I just don't understand the whole concept of "varying track voltage" through the TIU and it's proper implementation?

I am so excited to finally be moving forward on my layout and I hope you can provide some hints or insight into solutions for my questions.

Sincerely,

Junior

PS. If all these topics are already discussed elsewhere in the forum; I would be immensely grateful if someone would point me to them.

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Last edited by Junior
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I do what you want to do, using 6 TIU channels, 2 fixed, 4 variable, on my 38x16 layout.  This includes running conventional anywhere on the layout at any time.  Only difference is that I have a Z4000 with the Z4000 receiver driving the fixed channels, so I can control track voltage (i.e., control conventional speed) from the remote.  I don't know of any other way to do it, other than, of course, using the ZW handles when running conventional on fixed channels.

I will add some tips from 70 years experience:  Have a toggle switch for each of your blocks so you have better control over conventional locos.  I do not think you have too many:  I have about 75.  Also, for a layout that size, do not use smaller than 14-gauge wire for hot and ground feeds to the track.  Also, have a circuit breaker in each ZW output, between it and the TIU input, since ZW breakers aren't worth a hoot.

Your images didn't come through, so I can't comment on the layout.

What you have planned seems a bit over engineered to me.  I don’t think you need more TIUs.  I could be wrong, but, I think you could do it with just one.  I have a 20’ X 20’ U shaped layout with four loops and about 400 feet of track (not including sidings).  I use two ZWs and one TIU.

What type of track are you planning to use? If you go with some longer (36”-37”) sections and/or flex track you could reduce the number of blocks needed.

 I don’t think you can change a fixed voltage channel to a variable voltage channel.  You CAN change a variable voltage channel to a fixed voltage channel.  That’s what I did with mine and I control conventional engines just the way that RJR said (with the ZW handles).

 The layout looks pretty nice, but I would be concerned about access to the center of the layout.  Do you plan to have any access hatches?

I disagree with Lehigh, now that I have seen your behemoth.  Definitely 2 TIUs, to have the benefit of more than 4 TIU channels.  If you already have the 4 ZWs, fine, they work very well indeed with DCS  If not, consider what I have done:  replace a ZW with one Lionel Powerhouse 180-watt feeding 2 channels.  Plenty of power and the quickest breaker I've ever seen.  CAVEAT:  Lionel apparently is changing the Chinese source for these, so there's no telling when they'll be available or what is their quality.

I'll ditto some of what Lehigh74 said. I run 400 feet of tubular track using all 4 channels of one TIU, and one Z-4000. It can run easily 4 or 5 engines at a time, though rarely is there more than 2 in opeeration. The DCS signal is 10's mostly with a couple of sections 8 or 9. No issues.

When I first installed DCS I was interested in being able to run conventional as well, but once I made the jump there was no looking back. I now run PS-2' PS-3's, TMCC and Legacy stuff exclusively. And they can all run together simultaneously with no problems.

You can likely reduce the number of blocks you are planning dramatically. I have never counted the exact number of mainline blocks I have, but it's likely not more than 20. You can use up to 10 or 12 track sections per feed for sure, but the length of the sections is not critical. So the more 30" or 40" straights you have the better. If you are using Gargraves track that helps, but your track plan looks more like sectional track. I see lots of spots on your plan where long straights could replace several single 10" pieces.

Consider isolating the center rail between track feeds to get less DCS interference between blocks. This is recommended, though many including myself have not done this, and it all works just fine. Also consider using either "magic bulbs" at the TIU outputs, or engineered "SD" filters to improve DCS signal in troublesome spots. Lionel type 260 lighted bumpers work well on sidings.

Ditto on switched sidings. You can use toggle switches, rotary switches, Atlas 215 switches, or even AIU accessory channels, but they should be switched. Ditto on the 14 AWG track feeds; though you could also use 16 AWG depending on where your TIU(s) are located.

Ditto the access points. You need to be able to get to all areas and it looks like you have some that will be a challenge.

Rod

NYC; Back before filters came along it was found that bulbs on the TIU outputs (or at the point of splitting the TIU output to the various track block feeds) produced better signal strength. Either #432 or #1445 bulbs work well as they are rated at 18 VAC. In this pic you can see the bulbs on the right hand side of the TIU at each channel output.

P1050243

The theory as I recall was that the coiled filament of the bulb helped to attenuate back reflections of the DCS signal, thereby minimizing cancellation, so the net result is overall better DCS signal strength. It has sure worked for me, as well as quite a few others. I have not had need for any SD filters. The only downside of the bulbs is they burn 300 ma of power each, but that is of no big concern.

Rod

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  • P1050243

Thanks for the great responses guys! Here's answers to your questions:

LEHIGH74
    1.  I'm using Lionel sectional track. This layout is not an attempt at a "scale" layout. And I'm a
         Lionel Accessories fanatic (I also marvel at Rube Goldberg machines :-) ) and Lionel Accessories
         are not what I would consider scale.
    2. Oh yeah....I am definitely putting in hatches. I found a post on OGR's forum that shows a very
        creative way one model railroader put in hatches. Also, the entire table is on wheels; so I can
        move it around.
    3. Using the ZW throttle handles to control the Conventional engines is the "rub" that I realized.
        I'm not sure how I would coordinate 8 ZW throttle handles whose power is distributed across
        54 Blocks and 8 Power Districts. Phew! That would be a challenge.....but I have to be missing
        something......isn't there a better way?

RJR
    1. Yep....I already own the 4 ZWs and the 2 TIUs. And since I already own the TIUs I figured I
        might as well use them.
    2. I own a 500 foot spool of 14-2 sheathed speaker wire that I will be using exclusively for track
        power. So, the DCS signal should not be a problem.
    3. Fast-acting circuit breakers and TVS diodes are definitely going in between the TIUs and ZWs.
    4. I like the idea of replacing the ZWs with power bricks. I might do that if the ZWs begin to act
        up. Do you know if the bricks generate a "chopped sine wave" like the Lionel's newest ZW does?

Rod Stewart
    1. Thanks...it's good to know I can go with double the track length for each of the blocks. That would
        definitely help cut down on the complexity of the wiring ahead of me.
    2. As I mentioned earlier, I'm using Lionel O gauge sectional track.
    3. I didn't note it on the layout diagram but yes, the center rail of each of the blocks will be
        insulated from one another.
    4. I'm planning to switch-control all the sidings through relays. That way I can mount the relay
       close to the siding itself; keeping the DCS power feed to the siding as short and as straight
      a line as possible (without doubling back to the toggle switch at the control panel).
    5. Yep....I'm planning to use 18-20 volt "magic bulbs".  And I love the look of Lionel's cast
        metal lighted bumpers. They will be installed at the end of each siding. Hmmmm.....
        realized just now that if the sidings are switched (and there's no power to the siding), I'll
        need to find a way to keep the bumper light lit! Maybe I can control it through the relay?

Thanks for ALL your great input!

Last edited by Junior

Junior, I hope you're on a concrete floor, because a table that size on casters will tear up anything else.  Also, moving it may distort alignments if not very rigid.

When you say sheathed wire, I think you mean 2 conductors inside a metal sheath.  I'll defer to the electronic, but my reaction is don't use it because of capacitance effect, both between the wires and between wires and shield.  I recommend single strand THHM cable, 14 gauge, which is available in various colors from Lowes and Home Depot.  This statement will no doubt being a fusillade from those with other preferences, but I'll stand on this, for price and for results.

If your TIUs are Rev L, current recommendations are to skip the light bulbs.

As far as I know, the PH-180 bricks are pute sine wave, because there is no way to adjust output voltage.  However, you won't be able to run conventional on FIXED.  My PH-180 feeds 2 variable channels.

 

"Hmmmm.....
        realized just now that if the sidings are switched (and there's no power to the siding), I'll
        need to find a way to keep the bumper light lit! Maybe I can control it through the relay?"

Not sure I get why you need the bumper light lit when the siding is not active? But that's just me. A neat thing about the 260 bumpers is that the light confirms when the particular siding has power, in case you accidentally select the wrong siding and can't figure out why the engine won't start up. (Don't ask how I know this!)

Rod

You also can use a Single Pole Double Pole Switch too. 

Just  insulated the center rail of your Bumper block.

---------1---------------/-/-----2----"O" light of the Bumper Block 

                    Insulated  your Power  Brake  = /------  

3-Power Supply ! 

----------------------------------------------------------------------------------------------------

1= Your Track. 

2=Bumper Track.

3=Your Power supply !

To your new Single Pole Double throw Switch.   

Good luck, John 

 

Hey RJR;

Yep.....concrete floor and the wheels are 4 inch hard polyurethane able to support a ton (pun intended) of weight. There are 6 legs; each with a caster and an option to add 2 more if need be. And the table structure is very solid; there's 1x4 cross bracing all over the place (initially tried 1x2 but the bracing would flex too much when a load was put on it). I've already been crawling on it laying out the actual track and it supports 200+ pounds just fine. I do have to make sure I lock the wheels in place; any jerking movement also moves the table :-).

The covering on the wire is a white flexible "rubber" (not sure exactly what it is) covering. No metal shielding....sorry if I used the wrong term (sheath) earlier......

My TIUs are several years old; quite a bit before Rev. L came out. But I can try them without the "magic bulb" trick.....that's an easy add-on.

Your thoughts on the power bricks make sense....no circuitry to vary anything. And yes...no varying that power unless it goes through a variable port on the TIU.

Hey Rod Stewart;

Excellent thoughts on driving the bumper lights off of the siding itself.....an instant indication of "no light...no power". And I won't ask how you know :-).

Why the lighted bumpers? Goes back to my Uncle having a train layout a gazillion years ago. What I mostly remember (I was 4 or 5 at the time....MUCH older now) was the shining red light on the Lionel bumpers. Stayed with me all these years. Amazing how something insignificant like that stays with a person......

NYC;

What an easy-peezy solution......simple and elegant....I love it. Even though Rod Stewart made an excellent suggestion.....I'm probably going to light them........may be :-).

Thanks everyone!

I don't use two-conductor cable, to lessen inter-wire capacitance, just in case it would attenuate the DCS signal.

As to the bumpers, they serve as lights to improve DCS signal.  I'd leave them fed by track power.  When my layout got DCS added, I found that lights on some sidings would improve the DCS signal on blocks other than the siding.

 

RJR posted:

I do what you want to do, using 6 TIU channels, 2 fixed, 4 variable, on my 38x16 layout.  This includes running conventional anywhere on the layout at any time.  Only difference is that I have a Z4000 with the Z4000 receiver driving the fixed channels, so I can control track voltage (i.e., control conventional speed) from the remote.  I don't know of any other way to do it, other than, of course, using the ZW handles when running conventional on fixed channels.

I will add some tips from 70 years experience:  Have a toggle switch for each of your blocks so you have better control over conventional locos.  I do not think you have too many:  I have about 75.  Also, for a layout that size, do not use smaller than 14-gauge wire for hot and ground feeds to the track.  Also, have a circuit breaker in each ZW output, between it and the TIU input, since ZW breakers aren't worth a hoot.

Your images didn't come through, so I can't comment on the layout.

Hi RJR;

I was reviewing my wiring diagram and rereading the DCS Companion and realized I totally misread the track block length recommendation. I read "5 - 6 tracks sections" per track block when in reality it's "5 - 6 track sections on either side of the block connection"! That certain helps simplify the wiring!

Currently I am at a loss in regard to how to wire the layout in a way that would allow me to run Conventional and Command engines on separate loops but at the same time; no matter which loop on run them on (again, using ZWs).

I understand that the Variable ports of the TIU are able to be switched between Fixed and Variable. But doesn't that imply that an entire loop of track can only draw power from one or both Variable ports on a TIU? Then when you introduce Power Districts; the whole scheme for running Command and Conventional engines goes out the window. I'm so confused. Any way you can ad a little clarity?

An entire loop can be run on one channel.  My longest loop is about0.9 scale miles long, with about 12 blocks, including passing sidings.  Runs on one fixed channel, fed from one handle of a Z4000, but with a Z4000 receiver to adjust its output voltage.

A variable circuit does not need to be set to fixed to run dcs.  Simply crank the voltage up to 17-18 and run.  To run a conventional and a dcs on same loop at same time, have conventional train heavier than dcs train.  You can slow down a dcs train without affecting the conventional, and speed up the conventional without speeding up the dcs.  You can reverse either without affecting the other, except dcs will lurch when reversing the conventional.

RJR posted:

An entire loop can be run on one channel.  My longest loop is about0.9 scale miles long, with about 12 blocks, including passing sidings.  Runs on one fixed channel, fed from one handle of a Z4000, but with a Z4000 receiver to adjust its output voltage.

A variable circuit does not need to be set to fixed to run dcs.  Simply crank the voltage up to 17-18 and run.  To run a conventional and a dcs on same loop at same time, have conventional train heavier than dcs train.  You can slow down a dcs train without affecting the conventional, and speed up the conventional without speeding up the dcs.  You can reverse either without affecting the other, except dcs will lurch when reversing the conventional.

Thanks RJR......lost sight that I could power an entire loop on one channel. I guess as long as that loop has blocks the signal won't degrade.

Sorry I wasn't clear about the scenario for running Command and Conventional engines at the same time.

What I'm hoping to do is this....say you have 2 loops of track labeled A and B. I was hoping to be able to run Command on Loop A and Conventional on Loop B at the same time OR run Command on Loop B and Conventional on Loop A.......at the same time. This now seems straight forward with your confirmation that a loop can be powered by one channel with track blocks. But when Power Districts are added to a loop of track; it seems its something that cannot be done because each Power District would get its power from a different channel (even though the Power Districts could make up a single loop of track)?? True?

Because you are using the terms channel and power district, I think we have a semantic issue.  Channel of course means one channel of a TIU.  But how do you define power district?

A DCS loco has no problem going from one channel or power district without a loss of control (use super TIU if crossing from one TIU's area to another).  Unfortunately, with conventional, when going from one TIU channel or power source to another, you'll have to switch handles or remote Tracks.

I don't understand your scenario problem.  If I'm running a conventional and a DCS loco on different loops/channels/power districts, I have the voltage for the DCS loco's channel set on17-18, and control the voltage on the conventional's route from my remote using the Z4k receiver or variable (depending on where it is.

 

RJR posted:

Because you are using the terms channel and power district, I think we have a semantic issue.  Channel of course means one channel of a TIU.  But how do you define power district?

A DCS loco has no problem going from one channel or power district without a loss of control (use super TIU if crossing from one TIU's area to another).  Unfortunately, with conventional, when going from one TIU channel or power source to another, you'll have to switch handles or remote Tracks.

I don't understand your scenario problem.  If I'm running a conventional and a DCS loco on different loops/channels/power districts, I have the voltage for the DCS loco's channel set on17-18, and control the voltage on the conventional's route from my remote using the Z4k receiver or variable (depending on where it is.

 

Hi RJR;

You are right, a Power District is a Track Block; but Track Blocks are a vehicle that allows for the creation of Power Districts. I think a picture of what I'm trying to explain would help immensely so I included one below:
Power District Sample
As you can see above (and per my understanding....please correct me if I'm off base on any of this), Track Blocks and Power Districts are physically the same. But Track Blocks give you the ability to spread track power across more than one transformer. In the drawing above, if a long, high amperage passenger train is running on the outer loop and the train is physically across Track Block 1 and Track Block 2, the power demand for that train is shared across Power District A (ZW1) and Power District C (ZW2). That way no one transformer has to bear the brunt of the entire load for that train. That's my understanding (and definition) for using Power Districts.

Using the same picture, say a Command engine is running on the outer loop and a Conventional engine is running on the inner loop (or vice-versa). Because of the way Power Districts are implemented above, there seems to be no way to control either of the engines independently....correct?

That's where I'm getting total confused. How can I wire the above track plan to run Command and Conventional engines on either loop at the same time (but NOT on the same loop), and still take advantage of using Power Districts? As you and I know, long trains (especially fully lit passenger trains with dual motor engines) can demand a lot of amperage; quickly overtaxing the output of a transformer. What ya think?

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  • Power District Sample

Now I see your problem.  "Block" and "power district" are not synonomous.  A power district is the area served by one transformer, or others would say one TIU channel, but a power district is composed of many blocks.

Your problem is that you are trying to have several transformers serve a loop.  Forget the need to alternate transformers.  Have each transformer, and each TIU channel, serve contiguous blocks.  That's what I do, and have no problem with many trains on each loop at once.

 

 

RJR posted:

Now I see your problem.  "Block" and "power district" are not synonomous.  A power district is the area served by one transformer, or others would say one TIU channel, but a power district is composed of many blocks.

Your problem is that you are trying to have several transformers serve a loop.  Forget the need to alternate transformers.  Have each transformer, and each TIU channel, serve contiguous blocks.  That's what I do, and have no problem with many trains on each loop at once.

 

 

HI RJR;

Yeah....that's what I thought. The concept of Power Districts works great if your you're running Command or Conventional solely. But as soon as you want to intermix them; Power Districts go out the window.

Thanks for taking the time to work with me on my "problem".

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