# dc/dcc combined? temporarily?



## MrDuane (Oct 21, 2011)

Getting there,

We've a contractor for the garage remodel for this month, yeah. so now I have to get my plans settled. I went ahead and got a dc thomas the train for the grandson so he could have 'his own', with the ez track for the carpet. but it got me thinking. so, here is a plan with two loops, one for my dcc, and one inner loop for his dc. could this work if there were insulators between the two track loops so he could pretend he's part of the overall one. so then some day when I can manage a thomas dcc we could switch it over to all dcc?


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## waltr (Aug 15, 2011)

If the Thomas section of track is totally isolated then yes, your son can run with DC while you run DCC. 
To ensure the DC and DCC section never get connected I would put another pair of track insulator several inches away for the first pair. This will creat a dead section of track as that if your son tries to run Tomas out of the DC section the engine's wheels will not short the DC to the DCC.


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## MrDuane (Oct 21, 2011)

lol, never thought of that, thanks,


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## NIMT (Jan 6, 2011)

MrDuane, 
If you send thomas over I can have it back to you in a day or two with DCC, It's only $15.00 for the decoder.


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## MrDuane (Oct 21, 2011)

oh, not bad, but I'll keep it dc until I have my track loop up first. that way he can enjoy it around the christmas tree come the magic morning. but I'll certainly be looking your way.


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## Artieiii (Apr 25, 2011)

MrDuane said:


> oh, not bad, but I'll keep it dc until I have my track loop up first. that way he can enjoy it around the christmas tree come the magic morning. but I'll certainly be looking your way.


Why wait MrDuane? The decoder will run just fine on DC or DCC (dual mode). I converted my thomas myself and added a DCC/sound decoder to mine. My wife asked me to set up track around our tree so Thomas will run in DC mode around the tree per her request.
-Art


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## MrDuane (Oct 21, 2011)

well, for starters, I've not built my layout yet, have to wait for garage remodel in a couple weeks. and he can enjoy it now for christmas under the tree on ez tracks.


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## NIMT (Jan 6, 2011)

MrDuane,
It is safe to run a DCC engine on DC.
It is not safe to run DCC and DC on the same layout with them connected. If you ran a engine across the isolated connection it would have catastrophic consequences to the DCC controller.
DCC unit's do not like being back feed DC voltage!
Keep them separate!


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## Massey (Apr 16, 2011)

You could in fact not only leave a section of the rails DC for your son but also have that section of track DCC with the flip of a switch. I would also do the dead space as well to prevent accidental jumps to the DCC section.

TO make the switchable tracks simply use a DPDT switch (center off would be best) and feed the DCC into one side, DC to the other side and then the center posts of the switch to the tracks. This would let you select the power source feeding the tracks so all trains can enjoy the freedom of DCC.

Massey


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## MrDuane (Oct 21, 2011)

thanks loads guys, info is always appreciated.


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## wjacob (Nov 26, 2011)

How then can the digitrax zepher dcc starter system run a dc loco and dcc?


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## tankist (Jun 11, 2009)

wjacob said:


> How then can the digitrax zepher dcc starter system run a dc loco and dcc?


they "almost" can do so with zero stretching. it works great on paper and somehow works in reality. but regardless it is not a good idea , please spend the 15-20$ for entry level decoder and stop torturing that poor motor.


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## Massey (Apr 16, 2011)

wjacob said:


> How then can the digitrax zepher dcc starter system run a dc loco and dcc?


When a DC engine sits on DCC rails you will hear a buzzing sound. This buzzing is the DC motor vibrating at the same frequency the AC signal from the DCC system. As the motor is designed for DC opperation it will not move, but current is passing through the motor and the motor is getting hot. It is also putting a large load on the command station and booster of the DCC system. 

To operate said DC engine the command station sends out a long "0" on the positive throw or the negitive throw of the AC signal to move the engine. This long 0 changes the current bias from equal to longer in one direction which will cause the motor to move. The frequecy of the 0 determines the speed of the DC engine. The DC engine is still recieving AC current from the rails even tho it is moving. This is stressful to the DC motor. Oh and the DCC engines will ignore a "0" signal on the rails so running a DC engine usually does not effect them. Another note to be aware of is a DC engine will draw up to 2x the amount of current on DCC as it would on DC. This is due to the "short circuit" that happens as the AC current alternates. Some times DCC layouts have trouble powering up when a DC engine is also on the rails. 

Like it was said above, spend a few coins and get a DCC decoder for the engine. It is best of all involved.

Massey


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