Switching power source from DCC to DC

[Old Jedi]

I am building a DCC layout.  I do have a couple of older DC locos.  While I know I do not want to run them on the layout with DCC power (i am using a Prodigy Advance 2) I don't know about this:  Can I just unplug the command center and plug in a DC power pack and run the layout that way occasionally?  I will have two auto reversers in the buss--will DC do any damage to them?

[Nathan]

You will have to read the manual for the auto reverse units.  The ones I have, Tony's PSRev says they are not for DC.  You may have to put in a switch to remove them from the circut when using DC and add a DPDT switch to do the reversing section.

Also think about any DCC turnouts you may have attached to the layout.  You may want to put them on a seperate 'feed' bus that you can turn off also.

[SteamGene]

Old Jedi,
Feel the Force.  You may run ONE DC loco on address 00, but only one.  The danger is letting the DC loco sit on powered DCC track.  You do not want to do this.  If you have a siding where power can be turned off and on, your DC loco could rest there. 
Most today feel that mixing DC and DCC is not a good idea. 
Gene

[Old Jedi]

Well, that's pretty much what I thought.  I think it would be just as easy, and better in the long run to convert the old locos or discontinue their use.  The reason the new layout is DCC is looking forward, not backward.

[SteamGene]

Feel the Force.  I use DCC, but some of the model railroaders I respect the most do not.   It is new, but, in truth, some of its claims in the beginng have developed little coughs.  For instance - with DCC you don't need blocks.  No.  Now they are  - what are they?  Bigger, and for distribution of power in general and all up at the same time, but wired individualy.  In addition, I have the loco storage areas "blocked" to keep 20 sound powered locos from coming on at the same time.  Wiring is simpler.  Yes, it can be.  But a large layout is going to entail more complex wiring than some can handle - I know I needed and appreciate the help I received wiring mine. 
I don't think DC has gone the way of the key wound locomotive. 
But I don't think mixing DC and DCC is a good idea.  That had been my plan until I started reading more.  If you have mixed DC and DCC you MUST have some safety measures that may not be ignored - like moving a loco from a DC powered block to a DCC powered block. 
Gene

[Yampa Bob]

I only have a couple DC locos, it's just not worth the effort of changing power packs for their occasional use.  Of course, I could run them one at a time on address 10, but I don't want to chance ruining them. 

One is an ON30 Roaring Ridge, my wife's actually, which sits as a display on the buffet. I suggested adding a decoder, she said "Leave it alone".  OK, I can take a hint.  The other is a tiny Bachmann 4-4-0 we call "Wild Thang", goes airborne at half throttle.

I don't think DCC is the "wherewithall" for modeling, but I'm glad now I made the switch.  I have a small DC powered test track in my shop, handy for breaking in new DCC locos and troubleshooting. You might consider something similar to run your older DC models until you get them upgraded. 

[hotrainlover]

Old Jedi,
I have BOTH DC and DCC on my layout.  I had DC block control originally.  I put in a toggle switch that powers right, dead center, and powers left.  it shows like this..

ON/OFF/ON

One side is fed from DC power, other DCC.  The packs are both connected, and all I have to do is "flip" the switch.  Make sure you use the toggle that has a center OFF!

With already having block control, I can have visitors over, and let them run trains, without having to teach them the DCC system.  I just put the DCC engines on a siding, and turn off power to that siding.
Of course I can still run the DCC engines on DC, just one at a time!!

I also use a power indicator light that shows the layout has power going to it.  That way I visually know if the layout is "Dead".  I do this to know my wife will NOT put anything across the tracks and short it out!  Just last Xmas I went to "MY" room, just to find my main covered in decorations and ornaments, that would have shorted it out. 

[Yampa Bob]

I have thought about wiring in both my EZ Command and my Magnum DC pack with a switch, possibly another "roundtuit", but then I would have to remove a dozen DCC locos when running DC.  It's a great idea if you have a lot of older DC models.

One caution about using the switch "off" position to kill power to the track. You should also have a switch controlled power strip to plug the AC power supplies (wall warts) into. The controller itself should be dead before placing or removing a locomotive.

You would be surprised how the "Phantom Loads" of all the little wall warts around the home can add to your electric bill. Also, I wonder how many modelers leave their layout powered while unattended.  When I'm away from the track, the one master switch kills everything.

Just a thought.

[pdlethbridge]

When my brother switched to DCC, he had a large control panel with DPDT and SPDT switches. it's still functioning as a control panel in DCC. One thing was added, a DPDT switch to allow DCC or DC operation. This is an advantage at the present with many engines that are DC only, mostly brass. As they get converted the use of the control panel will diminish The only thing that would be saved would be the SPST switches for all the tracks in the roundhouse. When controls are added for the switchmaster turnout motors, such as Digitrax ds 64s, and an auto reverser is added, the DC system will be no more, neither the huge control panel.                         

[Jim Banner]

If you want to switch back and forth between dc and DCC but don't like the idea of having to remove DCC locomotives when running dc, just subtract 4 from the value in CV29.  That will shut off power conversion.

[hotrainlover]

Bob,
Yes you are right about the power switch...  I forgot to mention, that the light was a wall switch, that ALL power feeds through..  That is how I know that the layout is dead.  Thanks for the correction....