Recently a fellow model railroader asked if it was possible to to DCC a Plymouth CR-4. You remember what a CR-4 Plymouth switcher is right? Tyco was the company that put it out on the market.
This is what it looks like.
He suggested using a super magnet to replace the one that comes with the motor. I told him it might not work. I had a suggestion. Replace the motor with a can motor. The follwoing shows how I did that.
This is the dissasembled model.
First remove the magnet by grinding out the rivet.
Next grind out the rivets holding the motor together with the bottom plate.
Next grind the rivets holding the brass bushing retainer strips.
Remove the worms, bushings and commutator/wire armature.
Next I drilled and tapped the holes to hold the brass bushing straps using 0-80 scrrews. Turned a pulley with a V groove for the drive belt. Also ground relieve slots for the belt in the frame.
The motor is from a reduction drive. I used the one plate and a piece of brass to make a motor mount. Also a pulley was made and Loctited to the shaft.
The drive was first used by Tyco/Mantua in their “F9A”. Which looked exactly like an Athearn F7A. Oops. At first, anyway, they only made an A. I don’t know if they ever did a B.
The F9A came with either one or two power trucks. Since the power trucks didn’t take up much room in the body, you could put upwards of a pound of lead in. Maybe more. And with its traction tires, it was a wallpaper puller.
The next loco was a low nose GP20. With a scale width body.
And then the coolest of the batch: A C430. It was the impression on me of that loco that “forced” me to pick up one of the new Bowser C-430’s.
And, of course, there’s this little switcher and, I guess, a trolley car–I never saw that one.
If someone ever felt compelled to do an updated model of this streamlined looking loco, I’d buy one. I did just pick up the BLI Plymouth switcher–it’s pretty darn nice. Double darn, even.
The real one is actually a CR-4. Here’s a photo of one:
You take an archeological find like that, make a smooth runner out of it with 4 wheel pick up, both axles driven. For todays manufacturers building such should be a snap. And yet if modelers want “critters” of this size, it’s up to them to devise or modify drives. I don’t get that.
There are several. Athearn/Roundhouse did the EMD Model 40, BLI has a new Plymouth. For more modern fans, BLI has done Trackmobiles, and Overland did them in brass.
Yes that belt drive is smooth and quite. The Britts have discovered that quite a while ago. That’s were the inspiration for the drive came from. Hollywood Foundry uses the same kind of drives. Gives better control of top speed since you can make custom pulleys to get the correct speed. Not so with gearing. Could be done but a bit harder to do.
I did a complete rebuild of the Athearn Hustler drive train. I wrote it up on the Rail Line Forums under mid-size models. Search with the term Hustler and my name. You’ll get a complete write up of some of my miss-adventures in model engine mods.
Here’s a picture of the Cary shell on what’s left of the Athearn Hustler frame.
Here’s the modified drive train. I used parts from a Hobbytown drive.
And a video of it running. It had a ticking noise in one direction, but it eventually went away.
Thanks Dave. I have a Sherline 4400 long bed lathe. Nice machine for work like this. Also have a CNC Sherline mill and a Grizzly mini-mill.
Here’s the set up for the pulleys. The belts are square so a 90° groove needs to be cut. I ground an 1/8" HSS tool to 90°. I plunge cut so the belt is even with OD.
Then I use an 1/8" HSS tool bit ground for cutoff. The cutting end is about 1/32" wide.
Nice to have small tools like this to make custom parts.
