What could happen?


callouscade

New Member
Hey everyone.

I'm working on my new N scale layout and am building a control box that can switch the tracks between conventional DC power and DCC power. My question though is:

What would happen if I accidentally put a DCC equipped locomotive on a DC track? or vise versa...

My assumption is, if a DCC train was put on DC track, it just wouldn't move because it's getting no signal. Unless the decoder is setup to work on DC as well, I believe I read a few that do this. But if a DC train was put on DCC track, it would just be running at full power, ignoring whatever signals the DCC is putting out?

Am I somewhere in the ballpark?

Thanks
Cade
 
DCC engine on a DC track- no risk. If the engine is set up to operate on DC it will run, if not it won't, change the configuration to operate on DC.

DC engine on DCC track - The engine can over heat and the motor can burn up, or it can run full tilt. Digitrax is set up to operate a DC engine on address 0, NCE doesn't give you that option because they are afraid it will fry the DC motor.

Accidently connect the DCC command station to DC power on the rails - Can cause the DCC command station to fail.
 
Thanks for the reply! I have it setup so that it it physically impossible to connect the DC to the DCC rail, unless I short the two tracks out, or run a loco through a switch accidentally when I didn't mean to.

I'm using the Dynamis by Bachmann, I don't think it can run DC trains, but as long as a few seconds probably won't cause harm, I should be fine. It's something that if it were to happen I'd be able to catch in no time and hit the kill switch.

Thanks
Cade


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If you are running BOTH DC and DCC at the same time on different tracks, the possibility exists to cross connect the DC and DCC whenever a locomotive or lighted car crosses the boundary between the DC and DCC. It is much safer to make the layout all DC or all DCC.
 
I'm aware it's much safer to do it all one way or the other... the I have quite a few old locomotives where it would be almost impossible to convert to DCC. The Dynamis detects shorts and cuts the power to the track if it detects a short of any kind. As long as I'm careful with my switch directions I'm not too concerned. Thank you!
 
Be aware that applying DC power to your DCC tracks (as in when a loco bridges the two) is not the same thing as a short circuit. It can (and probably will) do damage. Unless your DCC system specifically says that it is protected against DC voltage being applied to it, I would not risk it.

There's an old saying that there are two types of retractable-gear pilots: Those who have landed with the gear up, and those will land with the gear up. AKA malfunctions and/or mistakes inevitably happen. The same thing applies to model railroading. You WILL get a turnout in the wrong position or look away for a second too long at some point. Make sure your system can handle it when you do.
 
Thanks for the reply! I have it setup so that it it physically impossible to connect the DC to the DCC rail, unless I short the two tracks out, or run a loco through a switch accidentally when I didn't mean to.

I'm using the Dynamis by Bachmann, I don't think it can run DC trains, but as long as a few seconds probably won't cause harm, I should be fine. It's something that if it were to happen I'd be able to catch in no time and hit the kill switch.

Thanks
Cade


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Would it interfere with the DCC Control to put diodes in line to prevent the DC from ever reaching the command station?


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physically impossible to connect the DC to the DCC rail, unless I short the two tracks out, or run a loco through a switch accidentally when I didn't mean to.
That is the accident that can fry the DCC system. It will eventually happen.

I agree with the others. Make it so that a train cannot run through a switch and accidentally connect the two. I would put in a DPDT center-off switch that makes the entire layout DCC or DC not mix them on two loops that have a crossover.
 
A little known fact is that all electrical equipment is actually powered by magic smoke. Once you let that magic smoke out, the item will no longer function. ;)
 
Thank you all for your input! Here's what I've decided to do...

In order to simplify my blocks around the turnouts and the station, I've made 4 different center-off switches. Each switch will switch between DC and DCC, so that I can run either a conventional loco or a DCC loco on any rail. However, if will only run one or the other on the entire layout at one time. If I do decide to run a DC and a DCC loco at the same time, I will have a dead track between the two loops that either train is on, so that if there is some kind of crossover that's accidental, it will "short" to a dead track.

Yes, an accident COULD still happen... but I'm going to risk that for now until everything is converted to DCC.

Thanks
Cade
 
I only have a few DCC locomotives, and a bunch of DC. Although I use MRC Tech 6 6.0, which can switch between DC and DCC, I NEVER use the DC selection. Instead, I use a regular DC power pack for DC operations. A DPDT toggle on my control panel selects which pack is connected to the track. Left is DC and right is DCC. Each pack is connected to the 110VAC on a separate power strip, with its own switch. When I'm running DC, the power strip for the DCC is OFF! When DC power is on, track signals don't light up until the analog control is turned up, and the lights are proportionally bright. When DCC is on the signal lamps are full bright (I use 12-16v incandescent bulbs). So far, so good!
 



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