What are the power/transformer requirements for DCS to run two trains on two ovals connected by two turnouts on a 4x8 platform?

As a follow-up to that question, what would adding an AIU to run three turnouts and power other accessories, such as building lights, do to the power requirements? I have always powered the turnouts and accessories with a separate transformer that is basically from an old starter set. This has always been part of a temporary Christmas display.

I currently have two transformers that came with my boys' Protosound 2.0 starter sets, I believe they are both Z750s. These two sets have always been run separately in conventional mode. I also have a third transformer, that I mentioned before, to power accessories.

Any suggestions would be helpful.

I'll get you started while someone else could fine tune the hook up. I run two 150 ft loops (broken into sections with insulating conn.) and four engines at a time. I only have one 10amp transformer. I found that if I run smoke on all engines and too many lighted cars I'll trip the breaker. So I guess you could figure the amp requirement by adding up each engine/lighted car draw in amps. I read that figuring three amps per engine (roughly)? I don't have a meter yet.
http://www.railking1gauge.com/detail.asp?item=40-750
says 75 watts for a Z750. I think if you powered each loop with a Z750, and kept the accessory trans for the aiu, you'd run near the same (little less) as me. Did this help you? joe

It sounds like you're saying the transformers you currently have are enough to run your trains. Adding a DCS TIU and AIU to control them will not add to your power requirements. They are not power hogs. When you add DCS do not use the controllers that came with the Z750 starter sets. Get a pair of 50-1017 TIU/Barrel Jack Adapter Cables and plug the Z750 "bricks" directly into the DCS TIU. That should be all you need. The small amount of power needed for the TIU/AIU is probably near equally offset by not using the controllers that came with the Z750s. Go for it. Enjoy.

Rugsy --

Let's start with a way of thinking about yer problem, then proceed to solution. I'd ask ya to remember the following:

• In power, think "amps" not watts. Your Z750s are, i believe 4 amp supplies (i don't have one & may be wrong here), so that is what they will supply to ALL uses at once.
• On flat terrain, a DCS steam engine, running smoke & perhaps four lighted passenger cars is gonna need, say, 2.5 amps. Make it 3 to be safe. So one Z750 won't run both for long; i'd test this. Oh, do you have grades? YMMV, but they can add an amp.
• There are other loads: lights, TIU, switches, UCS tracks, accs. I havea smallish 60 sqft layout with a dozen buildings, street & yard lights, etc., and draw just over an amp from all sources. Yer gonna haveta plumb each of these loads to one Z750 or the other, detracting from yer track total.

Now the operational consideration: one of the joys of command is forgetting about power blocks and running trains sometimes on the same track. I suspect that you will find that that is effectively impossible with Z750s that run thru seperate TIU channels to each loop. And it IS an operational limitation you don't need.

For just two train operation (just! 'cause you'll be tempted soon enough for three trains under DCS) i'd get ONE Z1000 and wire all the track to it (through insulated blocks as instructed) and run the TIU & other loads off of one Z750. That'd be a cheap way to get six amps on the all the track -- no fooling -- thru a single channel and more than enough even to run a UCS on the acc transformer. Cheap too (maybe < $90?). A few bucks more will getya a Power Brick with even more power.

If yer really gutsy/cheap, you could custom solder/wire the Z750 bricks in parallel and get 8 amps from a single source (make sure in phase!). MTH sez not to, but several forumites have reported success with paralleling Z1000s. Then you'd have a single 8 amp source & no worries for two train operation. Or you may have a smoking molten blob of plastic . . .

Best of luck. I predict you'll find that DCS will drive other needs that will make at least one Z750 a backup unit. I run my two loop layout with 3 Z1000s. I commonly run two trains, smoking and lighted cars on one loop. It is flat terrain though.

-- gary ray

Thanks guys, I am looking at the prospects of adding DCS to our small layout and utilize the features of our Protosound 2.0 engines which are currently unavailable in conventional control. The investment of DCS is steep enough for a temporary layout without adding the expense of high end transformers. I would like to have a permanent layout someday, but with our boys being the age they are, space is being used for other things.

Rugsy, use the power blocks, but not the controllers of the Z750. Feed each into a Variable of one TIU. Use your old transformer to power the switches. Use a Radio-Shack wall transformer to power the TIU (it can also handle the minimal power used by an AIU if you want an AIU.

How does this sound? Run one Z750 brick (using the adapter) through in fixed power 1 on the TIU, then to the outer loop of track through fixed out 1, then use the other Z750 brick to go through in fixed 2 and out through fixed out 2 to run the inner loop of track. I would insulate the two loops from one another where they meet at the turnouts.

My two loops are ovals, one inside the other consisting of less than 25' of linear track each. I could then continue to use my extra transformer to power the switches and other accessories conventionally without an AIU, as I have done in the past.

What is the difference between going through the variable in/outs vs. fixed in/outs? From reading the online directions, it seems by going through fixed, I can power the TIU and track simultaneously, but the variable in/outs do not power the TIU. If I send power through the TIU, do I have to power the track separately?

I did see you cannot use conventional control when using the fixed in/outs. I do have my Lionel train from when I was a kid that would have to be run conventionally. If the method I described in the first paragraph is correct, could I run one loop on fixed and the other through the variable and be able to run my Lionel on the variable loop?

quote:

If I send power through the TIU, do I have to power the track separately?

No. The power goes through the TIU to the track. On fixed channels the power is passed through and a DCS signal it added. On variable channels the TIU acts as a variable controller and adds a DCS signal. A variable channel may be converted to a fixed channel with a few keystrokes on the remote.

Try this. Wire one of the bricks to Var1 In and Var1 Out to the outer loop. Wire the other brick to Var2 In and Var2 Out to the inner loop. Take two short wires and connect Var1 In to Fxd1 In. That will provide power to the TIU. Insulate the two loops as you stated and also add a center rail insulated pin in each oval on the side opposite the power connection to each.

When you are running your PS2 engines set the variable channels to FIXED. When you want to run your old conventional Lionel change the loop it's on to Variable and control it with the remote. You can still run a PS2 engine on teh other loop at the same time. If you want to run the old Lionel on both loops set them both to Fixed.

First, I want to say thanks to everybody for their advice. Each of you have been very helpful. I am a very hands-on learner and it has been a challenge to make decisions when I don't have the hardware in front of me, and I only have online instruction manuals to go by. And for me, the simpler the solution, the better.

Gary, I do have a follow-up question. I am using MTH Realtrax. I assumed I would insulate the inner and outer loops from one another by breaking off the connection tabs on the underside of the Realtrax pieces where the two loops join (both the center rail and outer rail). I've also read that this can be done by putting electrical tape in between where the tabs connect. You mentioned putting a "center rail insulated pin on the side opposite the power" for each loop. I guess I acutally have two questions about this. How is this done, and why do you do this?

quote:

Gary, I do have a follow-up question. I am using MTH Realtrax. I assumed I would insulate the inner and outer loops from one another by breaking off the connection tabs on the underside of the Realtrax pieces where the two loops join (both the center rail and outer rail). I've also read that this can be done by putting electrical tape in between where the tabs connect.

You don't need to isolate the outer rail, just the center rail is required. Break or tape, what ever you prefer, as long as it's electrically isolated.

quote:

You mentioned putting a "center rail insulated pin on the side opposite the power" for each loop. I guess I acutally have two questions about this. How is this done, and why do you do this?

Sorry, "pin" is a throwback to tube track experience. Isolate the center rail as you did between the loops. For the best DCS signal you want to have one direct path from the TIU to the engine. If you wire the TIU to a loop of track the DCS signal will go to the engine both ways around the loop and the engine may "hear" two commands a slight bit out of sync and not respond. By isolating the center rail opposite the connection you create one direct path to the engine. That's a very simplified theory, anyway.

Thanks again Gary, once you mentioned tubed track, I knew what you meant. I appreciate the simple explanations for why things are done.

I was really hoping that in the process of stepping up to DCS from conventional, I could use some of the power components that came with the boys' starter sets and not have to start all over again.

With everyone's advice, I feel comfortable at least getting started. When I finally purchase the hardware, I may be back with more questions.

Just when I thought I was all done with questions. I was reading back over everyone's advice. Gary Ray mentioned something I was wondering about. If I run two ovals, one inside the other, connected by turnouts that are insulated, and each oval is powered by a separate TIU channel (Var1 & Var2 for example), what happens when a train passes from one oval to the other? With each oval being powered by a separate channel, will the locomotive still operate without interruption or will I be limited to keeping each train on its respective oval?

DCS control will be seamless across all channels of the same TIU.

Rugsy --

As Barry sez, the TIU supplies the same DCS signals to each channel, so passing across channels doesn't have any affect on DCS engine control.

But . . .

Recall my point about your Z750 amperage capacity, which will limit the engines on each TIU channel (with Z750s) to more-or-less one. Even stationary, my DCS engines draw an amp or so, if i recall. So, with acc loads, moving a second engine onto a loop (even with one stationary) would be at -- or over -- a Z750's capacity.

A frustration is, the breaker pops while the other Z750 is sitting idle; now you see why people are willing to consider the kluge of paralleling the Z750 through one TIU channel for the whole layout: 8 amps everywhere! Not that i recommend it, mind you . . .

There's really no harm in the simple solution: as RJR sez, just wire up your current Z750s, one to each loop and run 'em. If yah pop the breaker once in a while, so what? Just be aware why it is happening, and remember that one train on each loop should work fine.

For reasons such as these, many DCS users ultimately talk themselves into 10-amp-a-TIU-channel power supplies. As Tim Allen might say: "Z4000s, Power Bricks & ZWs . . . grunt, grunt." With my small road i've held the line at six amp Z1000s.

-- gary ray

PS How the heck did you end up with two Z750s, anyway? I though the RTR sets all had Z1000s nowadays.

Gary Ray, again thanks for the info. After reading and re-reading your original post and several of the others, I am starting to get a grasp of how all of this fits together. Call me a slow learner. What you are saying about the two trains sharing power from one Z750 and popping the fuse makes perfect sense. 95% of the time, the trains will be running on seperate loops and I think I am willing to live with that for now (I think). If I had these trains in operation year round, I would invest in the better transformers.

As far as two Z750s, I believe that is what came with my two sons' starter sets. They are packed away with the rest of the Christmas decorations. I am certain one of them is a Z750, the other may be a Z1000 or even a Z500. I looked them up in one of MTH's old online catalogs and the sets were described as having Z750s.

I have only seen DCS in operation at one local train/knicknack shop. The day I was there to look at it, the "train guy" wasn't in and nobody else knew anything about it. Besides, he had the DCS hooked up to a Z1000 brick, then to a conventional controller, and then to the DCS. According to the online direction manual and all of the advice I have read here, you aren't supposed to do that.

Rugsy --

i'd just get the dad-gum thing up & running; there are plenty of Fathers days & Bdays in the future. Mainly, though, i'm trying to give you an appreciation of the underlying issues. Lottsa guys talk themselves into overkill on power; i prefer to understand the loads and incrementally acquire what i need. My last Z1000 brick cost me $60 mail order, on sale.

You are right on the controller: it uses pulse width modulation and is a bad thing to have between the TIU and yer engine.

A DVM meter -- particularly with induction AC amperage capability -- is invaluable for working around & trouble shooting a layout. My chinese one was <$50.

-- gary ray

Rugsy, if you set up the way I suggested above, you can run conventional locos & PS2 locos, even at the same time, and can go across the switches seamlessly. And you can use the DCS remote to control your conventional loco.

I would run it that way before spending $$$ on any new transformers. I don't know how accurate the Z4000 ammeters are, but I can run 3 trains on a circuit and never exceed 5.2 amps (smoke off); in fact, I use 5-amp breakers, which like fuses don't open at precisely their rated amperage & can take substantial overloads before oprning, and they only pop when there's a derailment.

I just wanted to give everyone an update. All of your advice was very helpful. I finally won an auction on ebay on a used DCS TIU and remote. Everything arrived today. I dug out the boys' MTH starter sets from underneath the mountain of Christmas decorations, discovered we had a Z1000 and a Z750 transformer afterall. Two small test ovals are currently being powered by the one Z1000 and the boys are having a blast with the new things they can do with their trains, but now I have another problem. How do you wire two boys to one remote control? Just kidding, thanks for your help.

quote:

How do you wire two boys to one remote control?

Simple, go back to eBay and get another remote !!!!

Glad every thing is working well for you. Enjoy.

RJR --

Your readings are consistent with my observations; smoke seems to add 'bout 0,75 amps (tho it varies), so a bit under 2 amps per engine without smoke. Even with lighted cars, smoke & grades, you should be able to drive three engines per Z4000 handle; four under more typical conditions . . . of course there are lash ups to consider . . .

I don't see why the five amp breakers; you seem to be leaving capacity on the shelf. Z1000s give more than the power you are using.

It is easy to check the Z4000 ammeters with just about any DVM. i'd expect them to be fairly accurate, although probably give a moving average reading to reduce displayed amp volatility. The actual values jump around far more than the Z4000s' i've seen.

-- gary ray