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.
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.
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
(please remove the "NOSPAM" to reply via email)
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?
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
Terry Flynn replied:
See my web page for one way of wiring DC.
Your website contains a wealth of valuable information, Terry. Thanks
Bill's Railroad Empire
N Scale Model Railroad:
Brief History of N Scale:
Model Railroad Bookstore:
Resources--Links to 1,000 sites:
When you are exhausted and fed up with having to be an electrical engineer in
to run your trains, come back here and find out about using DCC (Digital Command
DCC is several orders of magnitude simpler and easier to work with. With three
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
If you enjoy electrical engineering, then, by all means, engineer your heart
if you would rather spend your time operating your trains instead of having to
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
you never need to make any changes or modifications to one. How's that sound?
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."
I have plenty of things to figure out without messing around figuring out things
dislike. So do plenty of the rest of us.
Interest in electronics is like eating worms. A few people may enjoy doing it,
It has nothing to do with ignorance. I am quite good at electrical/electronic
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
simpler wiring required on the actual railroad is much easier to troubleshoot
you have done something wrong in construction. However, unlike conventional DC,
a DCC system is installed, you never have to do anything else to it. If it works
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
Only friends though, I wouldn't do it for money or compensation. There isn't
You said that, not me. I've never had any of those kinds of problems with my
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
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
back in? Especially if you don't particularly like wires and switches?
new track plan or improving your operating scheme might do something, but having
face yet another bout of electrical torture in order to realize that is surely
to turn me off much quicker than changing some track around. Since I use DCC I
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
or WHY it goes. I only care that it goes. Switching from DC to DCC removed 99%
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
real trains operate, then you need to remove the control from the tracks and put
inside the locomotive. DCC makes that possible with a minimum of fuss and no
be an electrical engineer.
If I had to go back to running A DC/block control railroad, I believe I'd just
the hobby. It ain't worth it to me to go through all that crap.
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
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
of knowledge, just an intense desire to avoid all possible contact with
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
outta me. I prefer to run the locals and switcher jobs.
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,
Product of a mixed marriage: Nickel Plate father, Wabash mother;
The bulk of the rubbish is coming from your end. You know perfectly well that
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
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
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
of track which is at full power at all times, and upon which each locomotive
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.
are no issues of block selection, and block locating and positioning with which
deal. There are no routes nor any route selection system to engineer, ALL of
you need to be able to do in order to engineer and construct a DC system that
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
the fact that I can independently control each individual locomotive unit and you
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
I to can control all my locomotives using DC when I chose. No difference is
the end result.
locomotive unit can
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.
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.
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.
No, it doesn't. You don't use DCC and its decoders, so you have limited
from which to draw your conclusions
Another specious argument. You divide the DCC power distribution into sections
a circuit breaker in each section, but it is infinitely simpler than doing so
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,
one goes to the other. That this is repeated several times does not make it any
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.
Terry's point is that the smaller the block, the less track you have to search
the problem. For every DCC booster block you might have 4 or 5 trains (the whole
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
problem reappears - there's your problem.
With DCC you can turn each booster block on until the problem reappears -
that major area is a fault.
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