Although I do not use DCC, I know that it is possible to wire older Athearn locomotives. One thing I do know is that the motor is removed and tape is used to isolate it from the frame.
Good Luck
Randy Johnson
All you need to add is a DCC decoder to each engine.
However...
Some things will depend on the age of the engine. I've tried to upgrade a number of engines that were 40-50 years old. One of them was actually good enough to keep on the layout after adding a decoder. If the engine runs well on DC, though, then it should still run well on DCC.
You may need to isolate the motor from the frame. My old Athearns used the frame of the engine as part of the electrical circuitry. That's a no-no with DCC. Generally, this is as simple as removing the motor, insulating the base of the motor with a piece of styrene or electrical tape, and re-mounting the motor with nylon screws, not metal. Then you can re-wire.
Some older motors may be big-time power hogs, so much that they will exceed the capacity of the decoder and fry it. You'll need to watch out for this, too.
Yes, you can replace the motor and wheels, but by that time you may find yourself spending as much as a new engine. That's what happened to me. I "neutered" my old engines by removing the motors, and now they run as dummies.
It takes an iron man to play with a toy iron horse.
MisterBeasley wrote: Yes, you can replace the motor and wheels, but by that time you may find yourself spending as much as a new engine. That's what happened to me. I "neutered" my old engines by removing the motors, and now they run as dummies.
That's what I was worried about!
What it came down to was running quality and detail level vs. sentimentality. I had a pair of old Milwaukee Road Athearn GP-9's from the early 1960's. One was a gear drive, and the other a rubber-band drive. Both kind of ran, crawling around the layout, with a lot of irregular sputtering and stalling.
I found 2 brand-new Proto 2000 Milwaukee GP-9's online for $40 each. A new motor and wheelset would have cost me more than that, and the Proto engines run perfectly and have far superior shell details. There's just no comparison.