Are any modifications required?
I know that Atlas makes a “duel-mode” decoder that can run off of both dcc and dc, but I don’t know if anyone else does. I’m really not too familiar withh dcc, but I’m sure someone else will be able to give you a better answer.
Yes, if you set the appropriate value in CV29. One of the bits in there controls whether the decoder recognizes DC power or not. The default for most decoders is to have this bit ‘on’, so no modification would be required.
However, it’s been my experience that a DCC-equipped loco runs slower on straight DC power. You have to crank the throttle up a bit to get the same speed out of the engine.
Yes.
The Atlas dual-mode built-in decoders have a jumper board that has to be moved to a different set of pins to activate the DCC decoder; in the default position, the loco runs on DC only. With the jumper in DCC postion, CV29 controls whether it works in DC.
Practically any decoder can be programmed to run on DC by setting CV29, as mentioned above, but some decoders tend to overheat when running this way. Most decoder documentation advises against this on a long-term basis, with the possible exception of the Atlas dual-mode decoder which can be set to run on either DC or DCC by opening up the locomotive and moving a jumper plug.
Some will, some will not, and some of the latter will let all of the $$$$ smoke out of the decoder, voiding the warranty at the same time.
Broadway Limited converts automatically to DC, along with the Atlas that others have mentioned. The CV29 will set the ability to change, if your decoder has the capability. Some Digitrax will also convert.
On the less expensivce side the Bachmanns run on both automatically.
RMax1
Most decoders should be smart enough to either run or do nothing when DC voltage is applied, depending on how they’re set up. If the decoder is set up to run under DC (which is generally the default), they won’t do anything until the voltage is close to 5 volts, since the decoder will need that much to operate.
That said, if you want to do a lot of DC running with your loco, you should really unplug your decoder and run it as an analog unit (you may need to buy some special jumpers to do that)
How about on the Atlas N Scale SD60M (Item #49289)?