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I am using 2 MTH Z-4000s and one TIU for a 3 level track plan.  Does this look like the best way to hook up the wires for running both PS2/3 command and conventional trains?  Since the first level would be most often used for command, I thought the fixed outputs would be best to use there.  And then I thought it best to hook up my 2nd Z4000 to the variable outputs for levels 2 and 3.  I would like to run command on all tracks or conventional on some and command on others.  I don't need to run command and conventional at the same time on the same tracks.  I do have an extra TIU -- should I use that for the 2nd Z4000 instead of cramming everything into 1 TIU?  I have all of the books and videos on DCS including Barry's.  Your thoughts, fellas?  Thanks, MikeDCS PLAN 


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Thanks for your input.  My plan is to put toggle switches on every siding.  Other than that, I'm pleased to know that you agree this plan should work because I prefer to just use 1 TIU.  As I recall, when I met MTH at Train Fest, Dave (I think that was his name) said it was okay to use jumper wires on both transformers to stack power to a single TIU and power all loops as one and use the DCS remote to control the layout.  That seemed extreme, so I thought it might be better to run the 4 throttle handles of 2 Z4000s into the 4 channels of the TIU (2 fixed, 2 variable) for a cleaner distribution of power. That also would give me the option of actually using throttle handles instead of the remote to run those loops.

You can use any combination of power on the input side of the TIU, the only rules are, you can't connect TIU outputs together.  So, you could power the TIU with one, two, three, or four transformer outputs, totally your choice.

I actually have the variable channels on my mainline and sidings, that allows me to do conventional testing when necessary.  With the TIU variable channels configured in FIXED mode, it's pretty flexible.  Full voltage until you select a track and vary it's voltage, then it drops into variable mode automatically.

@IRON HORSE posted:


Thank you for your response.  That's good to know a real world example works.

On your fixed loops, theoretically, I believe, you ought to be able to use your ZW throttle handles to run conventional.   Reading through some old posts, I understand as you adjust the voltage on the fixed loops with your throttle handles your conventional engines should respond.

That’s exactly what I do.  I normally leave the ZW handles at 18V to run DCS.  If I want to run conventional, I use the ZW throttles to vary voltage.

But since I chose to power the TIU using Fixed 1, I don’t run conventional on that track.  If I lowered the ZW throttle on that input, the TIU would lose power.  If you power your TIU using the AUX input, it’s not an issue for you.

Thank you for that, John.  Clearly I misunderstood what MTH told me.  They were probably explaining what you said previously about using multiple transformers on a TIU and the outputs as well.  Cool.  I'm now ready to start crawling under my layout to do the wiring.  The last time I did that was in 2007 and I was in my 40's and thought I was getting old and my body wasn't cooperating very well!  Now I am approaching 60 and it'll be even more difficult.  Fortunately I built up a creeper to roll on and installed lighting under the layout before I begin.


John, please correct me if I am wrong; but won't he need a "Remote Commander with DCS Watchdog Generator" or have to adjust his operating procedures (example: power down the TIU channel, siding switch to ON and then power up the TIU channel)  if he intends to control power to sidings with toggle switches on the DCS Command levels so to prevent the engines from starting-up in conventional?

I’m not John, but…You don’t NEED a watchdog generator.  There are a few other ways to operate switched sidings with DCS.

  1. Switch the siding on before you power up the TIU.
  2. If you switch the siding on after the TIU has been powered up, the loco will generally start up in conventional (with smoke on). You then have to select the engine and push the START UP button on the TIU to make it run in DCS mode.  You may also need to push the SMOKE button to turn the smoke off.
@Lehigh74 posted:

I’m not John, but…You don’t NEED a watchdog generator.  There are a few other ways to operate switched sidings with DCS

You don't "need" one, but it sure makes it more convenient if you have a lot of MTH locomotives.

FWIW, you can also turn smoke and sound down for conventional, then it just comes up with the lights on, a bit less obnoxious.

Last edited by gunrunnerjohn

Guys, great tips on switching on the toggle(s) in siding(s) before starting up.  I did not know that.  You saved me some potential frustration.  Thanks.  I'm fairly new at DCS.  I have been playing with it for the past year or so on a simple loop while I have been building my new layout.  My previous layouts have all been totally conventional.

I love DCS.  I no longer think about buying any other engines than PS 2 or 3.  Perhaps when I start running conventional and command on different tracks with DCS I will change my mind.

I also have a conventional remote for my Z4000s and the phone jack plug ins.  Barry shows how to use those jacks with DCS and it looks like you can just plug them in and use the DCS remote to run conventional.  I'm still trying to figure out why that is a better way than just the variable channels.  I guess the jacks with Z4000s allow you to run conventional on the fixed output tracks.

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