# Too many loco for Digitrax



## riogrande51 (Aug 24, 2012)

I have been fighting now for about three months with Digitrax to help me with a problem. We finally fiqured it out we think I have 17 engines on lay at one time no all running but just sitting.
The problem is when I try to start up my layout or when I finally get it going a short happens such as a derailment my DCS 100 will not re set. If I take off about 4-5 engines off layout it seems to re set ok and starts uo when I start up.
I have heard of some sort of dcc circuit bord that helps this problem can some one help with this.
Is there a better Digitrax command station than the DCS100 that will work on a layout like mine 
I also have a Zeypher and a DB 150 that work great on my layout
Thanks
Riogrande11


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## D&J Railroad (Oct 4, 2013)

Sounds like you're not providing enough power supply to the layout.
What is the output of the power supply that feeds the DCS100 and BD150? and are they both powered off the same power supply?


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## DonR (Oct 18, 2012)

riogrande51 said:


> I have been fighting now for about three months with Digitrax to help me with a problem. We finally fiqured it out we think I have 17 engines on lay at one time no all running but just sitting.
> The problem is when I try to start up my layout or when I finally get it going a short happens such as a derailment my DCS 100 will not re set. If I take off about 4-5 engines off layout it seems to re set ok and starts uo when I start up.
> I have heard of some sort of dcc circuit bord that helps this problem can some one help with this.
> Is there a better Digitrax command station than the DCS100 that will work on a layout like mine
> ...


In another thread we were discussing a similar situation to yours. 
We were running 7 locos, 3 lighted coaches and 2 lighted cabooses
on a ONE amp controller. It shut down and would not reset until
we removed one loco. This is a protection against burnout.

I am assuming you have at least a 5 amp booster on your layout.

It's possible your controller is operating normally. 
You just have too
much load on it during the start up. You have those 17 decoders
pulling down power even tho the motors are not running. You have
lights on the locos, perhaps lighted cabooses or passenger coaches.
When you remove the several locos you are lowering the amp
load to a level at which the controller is programmed to reset.

Would it be possible to use an on/off switch on your loco storage
tracks that could remove some of the load at your start up?

Don


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## riogrande51 (Aug 24, 2012)

D&J Railroad said:


> Sounds like you're not providing enough power supply to the layout.
> What is the output of the power supply that feeds the DCS100 and BD150? and are they both powered off the same power supply?


I am running digitrax PS2012 20 Amp Power Supply 12 to 23 VDC I have 12 gage bus wire with 18gage every 2-3" max the power isn't the problem I tink the problem is to much compactor draw from all the loco even if they are not runing I have heard there is a way to fix this with taking loco off the layout or a switch that kills a section of the layout
thanks


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## JerryH (Nov 18, 2012)

Check the layout completely with the "quarter test" as outlined in the Digitrax manual. If you have unusual voltage drops around the layout, the current draw will go up. If a Zephyr could run 17 decoders simultaneously, then the DCS100 should have no problem either but they only recommend up to 10 HO per 5 amp booster. A DCS200 is rated at 8 amps. Verify the power supply is rated at a minimum output greater than the command or booster rating. There is an OpSw 18 to change the short circuit time in the DCS100. Refer to the manual to change that setting. The circuit board you mentioned is a PM42. You can set 4 zones with different trip currents or auto-reversing.


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## golfermd (Apr 19, 2013)

Up front, I don't have enough knowledge about Digitrax but will ask this question. Is there a limit to the maximum number of decoders your device can "control"? The control mechanism is software. Firmware is software burned on to an EPROM or other such device.


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## JJones (Nov 26, 2011)

I'm still very new to Digitrax but it sounds like you don't have enough power to your layout. a PM42 should help by only shutting down the section of track that has the short instead of the entire lay out but with as many locos as you have your going to need a good amount of power. how many of your locos have sound also? they require a lot more power then non sound locos.


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## ncrc5315 (Jan 25, 2014)

You need to break your layout into multiple power districts, each with its own booster/power supply. For instance, on a former layout, the engine tracks, had their own booster/power supply, with the adjacent yard having its own booster/power supply. 
PS, Digitrax, can handle up to 120 locomotives.


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## ggnlars (Aug 6, 2013)

The problem is that PS2012 is a power supply not a command station or booster. In general command stations and boosters are maxed at 5 amps. There are some larger ones, but their meant for the larger scales. 20 amps at 12 volts is a lot of Watts. Too much for small scale loco systems. 
Besides the power supply vs command station issue, there is a bit of confusion here. The latest DCC system can control up to 100 loco's, but they can not power that many on one station or booster. 
If you really want that many to be in play at the same time, you need to add power districts as indicated before. To determine how many you will need, several factors need to be consider. You need to determine the actual current draw of the loco's. Older and well used loco's will draw more current than brand new recent models. In the process, you need to include all possible current draws that may be in the district. Then you need to give your self some power margin. I would use three of your average engines for margin. 
Just for a mathmatical exercise to show what this means, I'll make the following assumptions. All of your engines draw 0.4 amp of current. The other electronics is a max of 0.1 per train. Thus, for a 5 amp system, the maximum number of single engine trains you can power is 10. To leave margin that I think is necessary, then you need to remove 1.2 amps or three engines, which is 3 single engine trains. So for these assumptions, the max per district is 7 single engine trains. 
Your going to say, but I can get my system to run a lot more than that. Yes, you probably can, but for how long. Stressing electronics to its maximum capacity always leads to early failure due to excessive heat. This is an area where you need to be conservative. Know what your current budget is and design you power districts accordingly.
Good luck,
Larry


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## DonR (Oct 18, 2012)

A 20 amp booster is a lot of power. Do I understand that
you are setting up several power districts, each with a
'breaker' device of some sort that would limit the
duration of any short circuit. With that much amperage
you could have some worrisome electrical events unless
there is some protection.

The PM42 seems to be such a device and would protect
4 separate districts.

Don


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## riogrande51 (Aug 24, 2012)

So I shouldn't be using digitrax PS2012 20 Amp Power Supply 12 to 23 VDC on my lay out and us some less is that what I am hearing. if so anyone want to by a power supply


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## JerryH (Nov 18, 2012)

There is nothing wrong with using that power supply. As a matter of fact it is the preferred one for your Digitrax systems except for the Zephyr which uses its own specific PS. There is a switch on it to set the voltage output according to scale however.


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## riogrande51 (Aug 24, 2012)

JerryH said:


> There is nothing wrong with using that power supply. As a matter of fact it is the preferred one for your Digitrax systems except for the Zephyr which uses its own specific PS. There is a switch on it to set the voltage output according to scale however.


got her set on HO so hope ther isn't two muchpower going to loco!


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## ncrc5315 (Jan 25, 2014)

The PS2012 power supply is what I use on my layout, I use one, to power up to four booster/command stations


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## DonR (Oct 18, 2012)

The loco will use only as much amperage as it wants. Usually
around .50 of an amp. The available
amps will do no harm to the loco. The reason you'd want to
use a variable circuit breaker in each power district is to have
a fast break in power when there is a short circuit so no
damage would be done to the device or whatever is causing
the short circuit. 

You are alright in your plans as I understand them. There is
no need to dispose of the big booster. You may need it as
you add sound locos to your layout.

Don


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## feldon30 (Dec 30, 2012)

riogrande51 said:


> I have been fighting now for about three months with Digitrax to help me with a problem. We finally fiqured it out we think I have 17 engines on lay at one time no all running but just sitting.
> The problem is when I try to start up my layout or when I finally get it going a short happens such as a derailment my DCS 100 will not re set. If I take off about 4-5 engines off layout it seems to re set ok and starts uo when I start up.
> I have heard of some sort of dcc circuit bord that helps this problem can some one help with this.
> Is there a better Digitrax command station than the DCS100 that will work on a layout like mine
> ...


You've got a DCS100. Regardless of the power supply, it's still a 5 amp command station and will only supply that much power. It sounds like you're asking it to do too much. Perhaps some of the decoders in those engines are not the best, or you have a lot of sound decoders which draw a lot of power?

As others suggested, a PM42 is one way to go, as you divide your layout into districts and then you don't lose the whole layout when there is a short.

A cheaper fix is to cut the railroad ties to your staging area and use a plastic rail joiner so that engines in staging are not pulling idle power. You would need to then put in a power bypass to provide power to your staging. Alternately, you could put a turnout which only passes power when it is closed. The point is, trains not in use would not draw power until you move them out onto the layout.


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## rrgrassi (May 3, 2012)

You can also use the DCS200. IIRC, it supplies 8 amps. A lot of current is drawn at initial start up. Think of it like a car. The battery has to provide a lot of amps at start up to power up the ignition system, starter, etc. Once the car is running, the amp draw is less.


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## GaryMartin (Jun 3, 2014)

Another thought, are you using decoders with backup power capacitors installed? If so, those will draw a lot of extra juice until the cap is charged up.


Now with everyone thinking on this issue, how would most of you wire a large turntable/roundhouse? I'd like to have a couple dozen steamers sitting around my turntable, all with decoders. (and probably backup power caps too)


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## DonR (Oct 18, 2012)

GaryMartin said:


> Another thought, are you using decoders with backup power capacitors installed? If so, those will draw a lot of extra juice until the cap is charged up.
> 
> 
> Now with everyone thinking on this issue, how would most of you wire a large turntable/roundhouse? I'd like to have a couple dozen steamers sitting around my turntable, all with decoders. (and probably backup power caps too)


The round house tracks may be one place you might want to consider an
on/off switch for each stall. Most of the time you would not want to have
their headlights on, and that could take the load off your controller. A SPST
for each is all you would need.

Don


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## riogrande (Apr 28, 2012)

feldon30 said:


> You've got a DCS100. Regardless of the power supply, it's still a 5 amp command station and will only supply that much power. It sounds like you're asking it to do too much. Perhaps some of the decoders in those engines are not the best, or you have a lot of sound decoders which draw a lot of power?
> 
> As others suggested, a PM42 is one way to go, as you divide your layout into districts and then you don't lose the whole layout when there is a short.


Bingo! The 20 amp booster does not supply 20 amps to the tracks, it is only a power supply. If you are using a single DSC100 command station/booster that is rated for 5 amps, that's the limit, not 20 amps. Basically your 20 amp power supply has enough amps to power four 5 amp boosters. If you are running a lot of engines at once on the layout, one way to break up the power drain is to break the layout into power districts so that a 5 amp booster powers part of the layout, and another 5 amp booster powers another part and so on, so that your engines are spread out across multiple power districts and no single booster is having to carry more than 5 amps. If you do have a single district like a yard that may have many engines running in it, more than a 5 amp booster can handle, you can buy the 8 amp booster and us it for the district with the most demand.

Cheers, Jim


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