All Nation/dcc

Those old open frame motors require a lot more current than modern can motors.

You could measure the current with a load on the loco and then make sure your decoder (or whatever its proper name is) inside the loco can handle that much current.

Roy is right about the open frame motors. You probably have 3 main paths with motors:

1. If it has open-frame and you want to keep it, you'll need a high current DCC decoder that's designed for G scale. I prefer Loksound but that's totally personal, TCS WOWsound and Soundtraxx offer great solutions that are readily available. You'll need to check they fit in this smallish loco as some are quite large.
2. Swap to a readily available used Pittman motor from an O scale loco, or another modern can motor which may have lower current draw. In this case you may be able to use the "medium-sized" decoder e.g. Loskound 5 L instead of XL.  
3. Upgrade to a low-current coreless motor that will let you use "HO sized" lower current decoders. You can but the motor and do the work yourself, or there are vendors such as Right-O'-Way who can provide a complete drive upgrade

In all cases but 1 and 2 especially, it's important to make sure your loco will always get to wheel slip under load before the motor stalls. 

The actual work would be something like this (excuse me if you're already used to DCC installs):

1. Swap out the motor and any driveline parts if you go that route
2. Plan out where all the new pieces will fit in the loco shell/tank and the wiring paths.
3. Add any lighting you want. LEDs are good these days with suitable resisitors, but incandescent lamps still work in metal body shells where heat's not an issue. Consider adding small plugs and sockects in all leads that connect betwen the loco chassis and the shell for easy removal of the shell later 
4. Ideally set up and test the decoder on the bench prior to install
5. Install the decoder and speaker if required, connect all lighting etc.
6. Have fun!!

I thought it wasn't possible to run an open frame motor on DCC, because the motor has to be isolated from chassis ground.  Am I mistaken?  Is there a way to modify wound-field motors to make them work like can motors in the DCC environment?

I run scads of open frame motors with DCC.    All of mine to date, including very old MG motors, have isolated brushes.    In HO I have seen many where there was a metal tab from the motor frame (which is attached to loco frame) to one of the brushes.   this has to be removed on these  HO motors.

I don't particularly care for sound.    It is usually too loud and gets annoying after about 15 minutes of an operating session.    I do have some some sound locos that came that way, and some I put a second sound decoder in.    but mostly my stuff does not have sound.

My decoder of choice is not a "G-scale" decoder, it is the NCE D408SR.    This decoder has a 4 amp continuous rating and a 10 amp stall rating.    It will handle any of the older open frame motors from All nation, USH, Max Grey etc. and works well with the Pittmans in the single motor drive Weaver locos.    It has 2 light functions plus 5-6 other functions that are programmable and can be  used for lights or whatever.    In my experience it provides very good motor control.

I don't rate decoders by scale - ie N-scale, HO scale, O scale etc.    I rate them by current rating.    I have used many decoders that are considered HO sized in newer O Scale locos that do not have heavy current draw.     They work fine.

As for motors, I find the old open frame Max Grey motors to be too slow for the my taste and generally replace them with a higher RPM motor.    I generally use the AN, USH, CLW and open frame motors unless they have another problem.    I have replaced any series wound motors I came across.    I think they could be run on DCC with the same decoder, but you would need a reversing circuit between the decoder and motor and that seems like too much work.

I have all nation F units that I converted from DC to DCC. I never bothered to check the stall current draw of the original all nation open frame motor. I just went ahead and replaced them with Pittman can motors that I bought from P&D hobby shop. I installed a TSC Wow sounds 4 amp decoder. Another issue related to DCC is the sintered iron wheels that some all nation diesels use. These wheels will pick up crude like crazy. I was very concerned about the electrical conductivity between these wheels and the track. When running in straight DC current I noticed arcing between the wheels and the track. My track is nickel silver. I polished all the wheels using 600 grit emery paper. This can be done in a lathe, drill press or even an electric hand drill. The original method of electrical pick up on all nation diesel trucks was that only two wheels on each truck where pick up wheels. I added phosphor bronze wipers to all the wheels so that now ALL wheels are pick up wheels. You can get phosphor bronze wheel wipers from Rod Miller. Next, I converted the engines to DCC by installing a sound decoder with “keep-alive” capacitors. These engines now run just as well as an engine with steel wheels. No arcing, no stalling and excellent slow speed performance with sintered wheels.

@prrjim thank you.  Your comment about SERIES motors in your last sentence is what I was thinking of.  Some open frame motors use a permanent magnet to energize the field.  Most that I have seen have a field coil (winding.)  I just assumed the motor in the original poster's All-Nation diesel was a series motor.

My experience is that motors with a field coil tended to fade away in Model use by the 60s.     Max Grey quit using them and started delivering everything with permanent magnet motors in the 60s.     I have never seen a USH loco with a field coil motor.     I have seen some much older All Nation locos with field coil instead of magnets but I think they were "General Models" rather than All Nation.     I use the term "Series wound" to describe motors with field coil windings - that may not be correct.    

But since the 70s, all the "new" open frame motors I have seen have had permanent magnets.    US Hobbies (USH) took over from MAX GREY in the early 60s I think and MG was already doing all their imports with Perm Mag motors.     The older motors in HO such as the DC 61 are Perm Mag motors.     I  I think the field coil type was used longer in 3-rail than 2 rail.    

For the All Nation switcher, the space for the motor, assuming 8 wheel drive is short.     Many pittmans cans such as used by weaver are too long.    Pittman did/does make a short fat one that will work and All Nation sold that as a conversion.     AN also had a shorter Perm mag motor used in those units as compared to the one in the F units.     So finding one of those motors might be a good idea also.

If the All Nation unit is one of the wheel drive versions with a self contained power truck, it is much more of a project to replace the motor.    It is probably possible, but a lot of mechanical work.

I have had no problems with All-Nation or Central Locomotive Works open frame motor conversions to DCC.  My standard decoder is the North Coast Engineering (NCE) model D408.

Thanks guys for all the help. Sorry it has taken so long for me to respond back. Work has been crazy with the holidays. 

I also use the NCE D408SR with many older open frame motors and they run really well.     All the ones I have including a few old max grey and many USHobbies, some CLW all are Perm Mag motors.    I have replaced a couple of series wound motors "just cause".

On the other hand, as I have just a switching layout, I use NCE HO decoders. The Atlas diesels I have rarely pull 1/4 amp.

Dick