# Cab Control Help



## ChristopherBishop (Sep 13, 2016)

I need some help and im hoping someone here could help me.. I've tried to read articles on Cab control and even as an Electrician, without the knowledge of model trains it's simply lost on me. To be honest, I'm not even sure cab control is what I need. DCC is not an option due to lack of capital.

I have 

- An Oval.
- A dogbone inside of the oval.
- Both are connected by turnouts on the top
And bottom of the layout. This way any one train
Can jump between the two by the top or bottom. 

I find myself wanting to run 2 independent trains most of 
the time, but don't want to lose the ability to jump between
tracks. However, the trains seem to draw too much from one transformer and one transgormer doesn't allow me to control the trains seperately. I essentially want a transformer for each track and the ability for the same train to be able to move from one track to another. Is cab control the answer? If so, how would I do it? Thank you to anyone who can shed some light on the subject.


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## DonR (Oct 18, 2012)

My goodness, I haven't seen the term 'cab control' in
a very long time, thanks to DCC.

You can control two trains on two separate ovals by
powering each with it's own power pack. Usually,
switched from pack A to pack B through a double
pole/double throw switch for each oval. There
are insulated joiners separating the two ovals.

You would need an ability to park one of the trains
in a 'dead' track when
you are switching the other from one oval to the other.

Then you would flip the switch so that both ovals are
fed by the same power pack. 

If you want to have more than two isolated sections
you would need a power pack for each, and instead
of the DPDT switch, you would use a rotary switch
with as many 'on' points as you have isolated
sections.

However, by the time you buy the additional power
packs, switches and wiring you are pretty close to
the cost of an economy DCC system and you do
away with all of the annoying switch flipping and
the need to park one train. One controller, one
pair of wires that feeds all tracks, and you can have
3 or 4 or more trains individually controlled, running
at the same time.

Don


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## MtRR75 (Nov 27, 2013)

Don't let Don scare you off. There are lots of modelers who still use DC cab control. It works well for running 2 trains a once. But Don is correct that trying to run more than 2 trains at once gets very complicated -- both operationally and wiring-wise.

Here is the best reference for how to wire and power a two-cab DC system. Everything is explained in detail and well illustrated. Written by one of the experts in model railroading. However, the DCC chapter is pretty sparse. If you change your mind and want to go to DCC, you would need a different book.

https://www.amazon.com/Model-Railroad-Wiring-Second-Railroader/dp/0890243492

It is true that there are lots more wires and toggle switches in a DC layout than with DCC. But if you decide to move up to DCC later, you can use your DC-wired layout without making any changes -- just leave all of the block switches permanently turned to Cab A.


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## MtRR75 (Nov 27, 2013)

One more thought. If you are trying to save money, buy your DC power supplies on the used market. Any power supply from MRC will do fine. There are lots of their older Tech II models available. I have two of them on my layout. One I bought new 20 years ago. The other I bought used about 10 years ago. Both still run perfectly.

Just stay away from the small power supplies that come with train sets -- like Bachmann. They are more cheaply made and often underpowered.


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## Cycleops (Dec 6, 2014)

Come on, why persevere with a system that is a hundred years old when DCC will do everything you want and more for not much more. Seriously DCC is just so affordable now. Don wasn't trying to scare you off but just illustrating how the cost of DCC has just come down so much that it's really only a little more than DC and much less fuss.


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## ChristopherBishop (Sep 13, 2016)

Do all of my locomotives have to be DCC?


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## gregc (Apr 25, 2015)

ChristopherBishop said:


> Do all of my locomotives have to be DCC?


yes.

See the Model Railroad Wiring for an overview










I'm an EE. I chose to use DCC on my small layout to simplify the wiring even though i have plenty of dpdt switches.


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## DonR (Oct 18, 2012)

Some DCC systems have a provision to run a DC
loco on your DCC tracks. While this is available
many of us are wary. DCC track has a continuous
modified 14 or so volt AC current. A DC loco sitting
on that track can overheat and burn out the motor
windings.

You can get DCC decoders for less than 20.00 each.
They are fairly easy to install. 

What some who have a number of DC locos do, is
power their layout through a DPDT switch, one
way it's DC, the other way it's DCC. That way
you can convert your locos to DCC one at a
time and yet be able to run any of them. 

But, do remember to park DC locos on a 'dead'
track when running DCC.

Don


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## CTValleyRR (Jul 26, 2014)

I agree with the prevailing opinion here. While cab control in DC is certainly achievable, what you want to do is just so much easier in DCC. I strongly recommend that you take a hard look at DCC offerings from the major players (Bachmann, Digitrax, MRC, and NCE) before deciding that it's too expensive for you. When I got back into the hobby in 2001, I thought I would need about a grand to get into DCC, but it turned out I was able to do it for less than $200 (although I've since upgraded).


Both Bachmann and MRC offer so called "DCC-Lite" systems (EZ Command and Prodigy Explorer, respectively) that are both very affordable and super easy. Their chief drawback is that they are not expandable, so if the DCC bug really bites you, you have to purchase a more comprehensive system.


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## MtRR75 (Nov 27, 2013)

DonR said:


> You can get DCC decoders for less than 20.00 each.
> They are fairly easy to install.
> Don


True, IF you have locos that are DCC Ready -- meaning that they have a wired socket under the shell (or in the tender of a steamer) that you plug the decoder into.

If you have older locos, you can still upgrade them to DCC, but you will have to rewire the inside of the loco somewhat. If you have the skill to do it, it is easy, but takes some time. If you don't, you will have to pay someone else to do it, which will raise the overall price of DCC.

Also, if you decide that you want to add sound to your DCC locos, the price goes up even more. Sound cards cost more than basic train control cards, and you also have to install speakers.


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## Shdwdrgn (Dec 23, 2014)

As someone who has never run DCC, I'd like to point out that for your existing layout it could possibly be considered overkill. There is one very important question that hasn't been asked yet -- _Do you plan on expanding your layout in the future_?

They are right that DCC control is easier, you have control each each loco individually no matter where it is at on the track, and if you have a larger layout running multiple trains, this can quickly become a tedious process under DC control. But if you are happy with your layout and have no plans for expansion, then DC can fill your needs.

So here's the quick version of running with DC... What you want to do is divide your track up into sections that make sense. The first split of course is between your circle and dogbone, and spurs would each be their own section, but you want to make more than that. Consider if you have both trains running, and one of them transfers from the inner to the outer loop -- you want enough sections where you can continue to run each loco from it's own power pack, and give time for the second loco to reach the turnouts and move itself to the inner loop, or perhaps you want a place where you can park one train and run the other one, without ever having the running train in a position that would apply power to the parked train. Does that make sense?

Now referring to Greg's drawing above, you use a switch to determine if each section is being controlled by cab A or cab B. And as the trains transfer between loops, you have to flip switches to *keep* each cab in control of its appropriate train. This is the tedious part, changing back and forth between sections. On the other hand, for normal running you just flip your switches so all of the outer loop in controlled by one power pack, the the inner loop in controlled by the other power pack, and just let the trains run.

Now in this scenario you *can* run a third train, but you have to continually flip switches and watch your speeds to keep each power pack under control of the correct train and prevent the trains from running into each other. And if you ever decided to include a reverse-loop to change train directions, you make the whole situation even more complicated, and you really don't want to get into that mess.

After picturing that, you can see why DCC becomes much easier -- you just set the trains on the track and control each one no matter where it goes or which direction it is traveling in. So if you're going to keep your current layout then you just need some insulated rail joiners and a bunch of switches to get started. If you have any plans for future expansion, then you're better off changing to DCC as soon as possible.


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