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I'd like some considered [the 'exercise' is not trivial] opinion re: the following technique for wiring a stub-ended yard, starting with the rationale behind it....AFTER emphasizing that I wish to operate 'everything' [conventional, TMCC, DCS] under the DCS system:  I have found that when an entire yard full of engines is powered up simultaneously that the DCS signal to a DCS engine is often 'corrupted', typically because a TMCC engine is 'too close' to the desired engine, EVEN when on a different track. I also want to be able to store conventional engines 'anywhere' in the yard, with no distinction/worry about what type of neighbors it has, which of course demands care in that I don't want to supply full voltage [say 18 VAC] to that track when starting up that engine. 

     With that intro, here's the idea:  On each siding, cut the center rail every 2 feet [say] and 'jumper' each resulting gap by an ON/OFF toggle that's located right next to that 'block', with track power supplied only to the 1st piece of track 'downstream' of the turnout that controls that siding.  Thus, to get power [and DCS signal] to the other [bumper] end of the siding requires that all toggles be ON.  Next, when moving the 1st engine into that track, bring it to the end, then turn the last toggle OFF, killing power to that engine.  Now bring the 2nd engine in to the farthest location possible, then turn the next toggle OFF.  ETC ETC ETC.  There is now a yard FULL of engines, with no power to any. 

       Now it's time to remove one of them, any one of those that was 'last in':  Simply set the turnout and throw the 1st toggle to ON.  Power will now be supplied ONLY to that engine.  Start it up, drive it out and run it....unless it's the 2nd engine on that track that you wish to use.  In that case, 'stow' the 1st engine at some convenient location, return to that track in the yard, and switch the 2nd toggle to ON.  Now that engine, and only that engines, gets the DCS signal. [BTW, I'm not concerned with the 'watch dog' start-up signal....If it's a DCS engine and it starts 'loud & brite', I can deal with that.]

    I THINK I've conveyed the scheme in sufficient detail to be understood.  Clearly its' a  bit complex, but consider the positive aspect:  ONE & ONLY ONE engine of ALL present in the yard gets the power + DCS signal.

   Now for the other, potentially 'fatal', downside:  Sending the DCS signal thru multiple toggles may weaken it so that the whole scheme 'goes up in smoke'. If so, would it help to use DPST toggles, so both HOT and COMMON go thru the toggles?          THAT'S IT, FOL;S!

         

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I'm guessing this would have been more suited for the Electrical forum, but that's water under the bridge.

 

This seems very complex for a questionable gain.  Why do you think you need power control for every two feet of track?  Also, I'm guessing that your concern with signal degradation is well founded, the 3.27mhz DCS signal will probably be degraded running through a couple hundred toggle switches!

 

The cost is high, the utility is questionable, and the prospects for it working problem free are dubious. Also, having the DCS engines start up in conventional mode and having to take extra steps to turn them off seems to detract from the utility of the technique as well.

 

I don't want to rain on your parade, but I see this as the answer to a question that shouldn't have been asked.

Phil,

 

I agree with John. This scheme is way over the top to solve a simple problem. Further, a string of toggle switches only needs one noisy one to mess up the DCS signal big-time. Even if you had each toggle controlling a track section as a "real" siding, instead of as a string of track pieces, you would be weakening the DCS signal through a great many splits.

 

The only issue you really have to deal with is the interference with the DCS signal by some, but by no means all, of your TMCC or Legacy engines. A much more cost-and-time-efective solution is to insert a 22 uH RF choke in line with the offending engine's pickup rulers. (This is discussed of page 152 of The DCS O Gauge Companion 2nd Edition.)

 

As for being able to maneuver engines around each other, you would be best off segregating your conventional engines from those that are command controlled. Then, stack the command controlled engines on sidings any way you like, since each one is individually controlled.

 

If you like, the conventional engines can then use the original scheme that you proposed, as long as you don't put a DCS signal into those sidings.

I will add that it would be far better to use relays right at the tracks to switch the power and control them with your toggles.

DCS works better without running it back and forth to switches.

And Barry is right, that many splits in the signal will degrade it severely.

You will need several TIU's to drive that many sections. VERY Costly.

Hi,  Barry's solution is your probably your best answer.  I keep the conventional engines on different sidings from my command control engines on my layout.  It works out fine.  I can only run one conventional engine at a time anyhow the way my layout is wired.  I can run 4 command engines at the same time.  This requires four operators which I seldom have.  I can't get more than 4 people in the layout room anyhow.  

 

I haven't had problems mixing MTH and Lionel command engines on the same track.  Perhaps I have been lucky so far.  All of my sidings are controlled by a single toggle switch.  I turn the power off to each siding when I am not running on a train on the siding.  

 

Joe

Matt,

I would tie the individual toggle switches to a terminal block and straight to the track segment. That way you only have a single toggle switch between your TIU source and the track.

Depending upon how many sidings we're talking about, that could cost a lot of money for TIU channels. The typical pre-Rev. L TIU channel can be split about 12-14 times on a terminal block before one encounters DCS signal reduction.

 

A Rev. L channel can handle more splits, however, I don't have an upper limit number because, at 18 splits per channel, I haven't encountered a decrease in DCS signal.

Hi Phil, I'm glad to read that you have given this alot of thought. I agree with the others who say this plan is a little to much work to solve your problems.

As for the switch idea Barry made a very good point about noise. But, that said I have thought about this question as well but in no way to the complexity of your scheme.

I am considering a STAR plan, as was suggested by MTH from the beginning of DCS. But, with my idea each block would go through a DPST switch off of each leg of the star, with no more then one switch per leg. The negative on one pole and the positive on the other.

My logic in this is to keep the Go/Return balanced between negative and positive. Also if you do get a bad switch it will probably only effect the engine on it's block. 

As for your conventional engines they should come off of one of your variable poles of your TIU using the same plan as I mentioned above.

 

In any case, I'm thinking about a small yard with only a few switches and I'm not to sure that it would not create more problems then it's worth. Mechanical switches can be a real question mark when dealing with any kind of signal through them.

 

What ever you decide to do good luck, have fun and keep us posted.

Good idea John, I think that's the way I'll go. What I spend on relays I'll save on wire, almost.

But it dose make things alot simpler.

I just got another idea that makes relays a better idea, I bet I could drive them through my AIU. Command Control baby!

 

Oh yea, Thank's to you too Russel.

Last edited by gg1man

Hi Ed, when we are talking about a noisy toggle we mean the contacts in the switch it's self. Sometimes the contacts can be fine for a DC, or 60 cycle AC current but a little slop or dirt can really hurt a data signal. That is why switches like relays come in diffrent types of contacts, gold, silver even platinum. Some may be rated for high current and others may be rated for high frequency. But, what I was talking about was mainly the potential slop in a hand thrown mecahnical switch.

Can they work in this application? Of course, but not as well as relays because the relay is right near the block in question and it's closed electrically, that is a much faster and smooth operation. 

 

As far as your question about your switch; take an alligator jumper and use that between the terminals of the switch. This will by-pass the switch contacks and if your problem persists then you need to move on to other causes. If it works then the problem is with your switch, install a relay in place of the switch.

Allen wrote: "Too many folks try to "over-engineer" this hobby, thereby making it far more complex, time consuming, and costly than it ever needs to be...regardless of whether one runs conventional or digital command control."


I dont run command or dcs or tmcc or.....  as I posted in another post, I almost finished an electrical engineering degree.  I was always employed in the the cabling industry. I LOVE MASSIVE BUNDLES OF WIRE!!  if I were to have it my way I would have a "Termination" room just for the sole purpose having all my relays and home made logic circuits in one area. I could find it almost as fun to sit in the door way of such a room looking at (and listening to) all the relays and wire and watching the logic status LEDS flashing about as fun as actually watching the trains.  


Yep, I need to get a life!! RW

Right on Ryan, I love doing the same thing. Sometimes when I take a break at work I can picture a relay circuit I'm working on in my mind and when I get home I can't wait to change the drawings to see if the idea works on paper. When a plan comes together and works it like seeing a train emerge through a tunnel portal, I just never get tired of it.

 

 

Originally Posted by Allan Miller:

Between this thread and the Lee Wills thread about his track problem, I'm developing a major headache.

 

Too many folks try to "over-engineer" this hobby, thereby making it far more complex, time consuming, and costly than it ever needs to be...regardless of whether one runs conventional or digital command control.

 

 

O-guage..........O-verengineer............O-verthink........ O-well.......I guess its a break from the "poor QC" threads. Funny how these things come in waves.

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