Voltage from two transformers

My new staging yard will have its own power supply. When a train crosses from the staging yard to the mainline, there will be a split second when
it will draw power from both MRC units. Does voltage double up -- will it be getting 24 volts for that interval -- and will this damage engines? If it does, I suppose I'll have to coast across the insulated joiners onto dead track, reduce the first throttle and then turn up the second throttle. The mainline already has two MRC 2500 units, and each block has a DPDT to determine which throttle controls that block. But I didn't want to have to rewire my control panel to include the new addition, so I gave it a separate transformer.
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Hi, Harry! harrym wrote:

crosses
when
will
No, voltage is not additive in this situation. As long as the polarity is the same for both adjoining sections, and the voltage level is the same, you should see no difference. If the polarity is not the same, your engine will try to go in two directions at the same time, and could be damaged.

the
each
I
You would be far better off to wire in a DPDT toggle switch and create a transition block on the yard lead or to one of the yard tracks that can be controlled by both the mainline and the yard power, depending on which way the switch is thrown. That way there's no danger of getting your reversing switches crossed up... And you'll find that HO scale (and most other scales) locomotives don't coast well at all....
--
Gary M. Collins
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If you're running fully independent supplies, the locomotive will stop because the supply and drain of the power aren't going to be connected. Use common rail wiring for best results. Better yet is to not do two different packs that each handle one area of the layout but rather switch between them depending upon what you are doing on a particular piece of track. A simple SPDT electrical switch will allow this for all of the sections (blocks) of your track.
-- Why isn't there an Ozone Hole at the NORTH Pole?
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crosses

when

No, voltages in parrallal will not double. Voltages will double if they are in series.
In this situation the pack with the higer voltage will overwhelm the pack with the lower vaoltage. There is a possibility that this could dammage the power pack, but since these powerpacks are designed for some pretty rugged duty anyway.... I wouldn't worry. We do this sort of thing regularly on our layout. WE have an extension that is controlled by it's own throttle. The main layout has it's throttles. at the transition the locos are pulling from both. Been doing this for some time with no problems.
--
Just my $0.02 worth. Hope it helps
Gordon Reeder
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See my web page for one way of wiring DC.
--
Terry Flynn


http://angelfire.com/clone/rail/index.html
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Terry Flynn replied: See my web page for one way of wiring DC. http://angelfire.com/clone/rail/index.html ---------------------------------------------------- Your website contains a wealth of valuable information, Terry. Thanks for sharing.
Bill Bill's Railroad Empire N Scale Model Railroad: http://www.billsrailroad.net Brief History of N Scale: http://www.billsrailroad.net/history/n-scale Model Railroad Bookstore: http://www.billsrailroad.net/bookstore Resources--Links to 1,000 sites: http://www.billsrailroad.net/bills-favorite-links
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When you are exhausted and fed up with having to be an electrical engineer in order to run your trains, come back here and find out about using DCC (Digital Command Control) instead. DCC is several orders of magnitude simpler and easier to work with. With three MRC packs, you've already spent as much as a DDC system would have cost you, and you still do not have the flexibility of operation you are looking for. For about the same money, and a lot less hassle, you could already be there. Don't stay stuck in the stone age of DC. There are far better ways to do things now. If you enjoy electrical engineering, then, by all means, engineer your heart out. But if you would rather spend your time operating your trains instead of having to figure out how to operate the track under them, come learn about the joys of DCC.
For starters, there is no need for a control panel. You never need to wire one and you never need to make any changes or modifications to one. How's that sound?
CH
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On Tue, 01 Mar 2005 02:50:36 GMT, Captain Handbrake @ ACL.com wrote:

And you'll never have to learn how to figure things out. Quit basing your opinion on the higher level of allowable ignorance. I would ten times rather chase an open or short through a DC circuit than have to try to find it inside a non repairable chip. (Usually non replaceable too, buy new board, trashcan blown one.) You get to learn how to trash the old board, because it's cheaper to buy a new one than repair the old. Microelectronics can be wonderful where needed, but I don't think I'd want to risk a $1000 brass Pacific to the glitches of a ten cent chip. Don't tell me it doesn't happen, I've played with electronics far too long to believe it.

Like a model railroad that's "finished" and three months later "boring." And again elevates the level of allowable ignorance. "Don't think, buy."
Greybeard
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What is it that you are risking?

What, "doesn't happen"?

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I have plenty of things to figure out without messing around figuring out things I dislike. So do plenty of the rest of us. Interest in electronics is like eating worms. A few people may enjoy doing it, most don't.

It has nothing to do with ignorance. I am quite good at electrical/electronic crap, I just hate doing it. So do many of us.

.....And I would rather shove needles under my fingernails.....
Fortunately, opens and shorts are extremely rare in DCC components, and the vastly simpler wiring required on the actual railroad is much easier to troubleshoot when you have done something wrong in construction. However, unlike conventional DC, once a DCC system is installed, you never have to do anything else to it. If it works when you turn it on it will work forever. Since it is so much easier and simpler to install, the likelihood that it will work as intended is much greater.

Hurrah for that!
I'll choose that option every time. And so will thousands of us that despise effing around with electronics. However, I do repair decoders that have been mishandled or damaged by their owners. Only friends though, I wouldn't do it for money or compensation. There isn't enough.

You said that, not me. I've never had any of those kinds of problems with my $1,000 brass Pacific since 1995, when I made the switch to DCC. I did have those problems in the stone age when an operator would over-run a block or throw the wrong switch or something similar.............

A specious argument at best. The interest is in the model railroad, NOT the electrical crap that makes it go. If it's boring because you don't know what you want, then how is farting around with wires and switches going to put the interest back in? Especially if you don't particularly like wires and switches? Engineering a new track plan or improving your operating scheme might do something, but having to face yet another bout of electrical torture in order to realize that is surely going to turn me off much quicker than changing some track around. Since I use DCC I can re-route and change my track daily, if I want to, with no thought given to the operating system that makes it all go. It just goes. I don't give a damn HOW it goes or WHY it goes. I only care that it goes. Switching from DC to DCC removed 99% of the frustration and hassle of model railroading for me. I can deal with the remaining 1% just fine. If you do not know how a real railroad is run, then DC will probably seem to be a perfectly fine system for operating the trains. If you really want to operate like real trains operate, then you need to remove the control from the tracks and put it inside the locomotive. DCC makes that possible with a minimum of fuss and no need to be an electrical engineer. If I had to go back to running A DC/block control railroad, I believe I'd just quit the hobby. It ain't worth it to me to go through all that crap.
CH
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@ ACL.com says...

How about I don't care how a real railroad is run? Some of us just like to build models, structures, and scenery and watch the trains run :-).

Yes, with a few exceptions that is entirely correct.
But don't attribute a lack of interest in realistic operation to a lack of knowledge.
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That's true, but not the thrust of my argument. You can't cover all possible interpretations in a few sentences. Someone is always going to see more there than you print, or extract a meaning different from the one you are trying to convey.

Now, if you don't care, then this is not meant for your consumption. You don't care. there's nothing wrong with that

I don't, anymore than I won't allow anyone to attribute a lack of enthusiasm for electrical/electronic workings to a lack of knowledge. For my part, there is no lack of knowledge, just an intense desire to avoid all possible contact with something I dislike very much. Others do not care at all for operations. We have two fellows like that in our group. They will go home before they will run a switcher or a local freight on operating night. Mainline through freight or passenger, nothing else. Suits the hell outta me. I prefer to run the locals and switcher jobs.
CH
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On Wed, 02 Mar 2005 01:15:45 GMT, Captain Handbrake wrote:

Some folks like to watch NASCAR roundy-roundy shows, others like road races on real courses. Roundy-roundy seems pretty boring to me, too - good thing you've got those guys to provide background scenery for the railroad, eh? <g>
--
Steve

Product of a mixed marriage: Nickel Plate father, Wabash mother;
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Spot-on. I don't care much for NASCAR type operations either, but I can really get stuck into an IMSA road race or a Grand Prix event. So then, it really is very much "each to his own", isn't it?
CH
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Captain Handbrake

seem to be a

and put it

Here we go again, the fiction that DCC controls the train from the locomotive but DC does not. What a load of rubbish. Both systems use the track to transmit the control signal to the locomotive.

--
Terry Flynn


http://angelfire.com/clone/rail/index.html
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The bulk of the rubbish is coming from your end. You know perfectly well that your way of doing things controls the way the track behaves under the locomotive. you transmit power to the loco motor either as a variable voltage or a pulse-width modulated voltage. There is nothing inside the locomotive that tells it that the power is or is not meant for it, so then, every locomotive on that piece of track responds to the command and they all do exactly the same thing.
My DCC locomotive knows when I want it to do or not do something, and so I can have the power to the track on at full strength at all times. since control of the locomotive unit is in the locomotive and not on the track under it, I can make any one of several locos all on the same track, move independently.
Now, expand that idea to encompass the entire model railway layout as a single block of track which is at full power at all times, and upon which each locomotive unit can independently be caused to behave as desired, and you begin to see the power and simplicity of the thing. There are no design obstacles to overcome or solve. There are no issues of block selection, and block locating and positioning with which to deal. There are no routes nor any route selection system to engineer, ALL of which you need to be able to do in order to engineer and construct a DC system that will behave almost as well as a DCC system that you can take home, plug in and run.
So, if you want to claim "rubbish", you go right ahead and do it. It doesn't change the fact that I can independently control each individual locomotive unit and you cannot.
CH
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Captain Handbrake

like
tracks
that your

locomotive. you

pulse-width
that the

of track

The motor responds to the average voltage it sees in DC, in DCC the motor responds to the average voltage it sees from a decoder. Neither matches the prototype.

can have

the
make any

I to can control all my locomotives using DC when I chose. No difference is the end result.

single block

locomotive unit can

power and

solve. There

which to

of which

that will

run.
What you advocate is the way to wire a DCC layout is only advisable for the smallest and simplest layouts. Large DCC layouts require electrical blocks to make fault finding easier, train location requires detection, electrical blocks with current detectors are a common method to do this. DCC requires electrical blocks for Y's and return loops just like DC.

doesn't change

and you

But the fact is I and others using DC also independently control each locomotive. It's electrically done a different way, that's all. The only time this is not true is when we choose not to. For example double heading or when using automatic control systems.
--
Terry Flynn


http://angelfire.com/clone/rail/index.html
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wrote:

things now.

heart out. But

having to figure

DCC.
things I

it, most

electrical/electronic crap, I

the vastly

troubleshoot when

conventional DC, once

works when

simpler to

When you get a short on a decoder output it usually means buy a new one. Shorts are as common on DCC as DC. Depends on the layout. If you keep your DCC wiring as simple as possible, that is one block, when you get a problem it is harder to fault find compared to a blocked DC layout. And until you find it, all your layout is non operational. If you block your DCC layout, it makes fault finding easier, and you now have a similar amount of extra layout wiring as a DC layout. A similar likely hood of faults developing.

their owners.

isn't enough.

my $1,000

a block or

wire one and

sound?
the
what you

interest
Engineering a

having to

surely going

DCC I can

the
HOW it goes

removed 99% of

the
to be a

operate like

and put it

no need to

just quit

--

Terry Flynn


http://angelfire.com/clone/rail/index.html
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No, it doesn't. You don't use DCC and its decoders, so you have limited experience from which to draw your conclusions

Another specious argument. You divide the DCC power distribution into sections with a circuit breaker in each section, but it is infinitely simpler than doing so with a DC/cab/block system. You will not begin to approach the degree of complexity and aggravating work that the same thing on a DC/cab//block design would require. You still have only two wires to worry about. The black one goes to one rail, the red one goes to the other. That this is repeated several times does not make it any more difficult or complex since the red wire always goes to the same rail etc. Been there-done that many times, both ways. I know what I am talking about.

CH>
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Captain, Handbrake, @, ACL.com wrote:

Terry's point is that the smaller the block, the less track you have to search to find the problem. For every DCC booster block you might have 4 or 5 trains (the whole point of DCC) whereas with analogue control you should only have one train. With analogue you simply turn off all blocks and turn them on one at a time until the problem reappears - there's your problem. With DCC you can turn each booster block on until the problem reappears - somewhere in that major area is a fault. <sigh>
Greg.P.
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