Help with ID for this motor?

Doing the best I can without it in my hands, I believe it is Lionel's evolution of the 622-100, the 610-8503-100. I believe it is a direct drop in replacement. The armature is either the 610-8503-125 or 600-8753-125, evolutions of the 622-109. It appears your armature may be the 600-8753-125.

Here is the parts breakdown:

https://www.lionelsupport.com/...C64-B4D5AFF1188481BA

Hope this helps!

Thanks @bmoran4, I certainly appreciate your response! I wanted to take a picture of the 622-100 motor side-by-side with the unidentified motor to demonstrate the different lengths of the armature shafts, but I also didn't feel like tearing apart a good running engine to do so! So here is the unidentified motor next to a 2321-100 motor. According to Bob Hannon) the 622 armature and the 2321/2322 armatures are the same length.

Unidentified is on the left, 2321/2322 on the right

As you can see, there's a clear difference in shaft length length, about 3/16" roughly, plus more threaded length on the worm. FWIW, the half-moon collar or shroud around the armature shaft on the left is 1/32" longer than the one on the right.

The total shaft length on the 2321/2322 armature is 2 - 12/32", spot on with what Mr. Hannon calls out, while the total shaft length on the unidentified armature shaft is 2 - 17/32", give or take a smudge.

So what i can't tell is if the armature has been replaced in my unidentified motor. I can tell you for a fact that the unidentified motor assy does not fit in the standard PW 622/623 motor truck (I tried!) - the armature shaft bottoms out before the rest of the motor is seated within the frame. But this unidentified armature had to go to some Lionel motor, if not this one, so that still leaves things identified....

I just noticed that the picture on the right makes it appear that both shafts are bent - they are not! Must be CCD (cheap camera distortion.)

George

Those comparison pictures are very interesting. I think your 2321-100 is actually an early 2028-100 (The armatures for both measures 2 15/32 according to Hannon). Here is an early 2028-100 armature next to yours:

As for the mystery motor, I think we may have a Frankenstein... it may be that a 600-8950-109 armature was installed from the 600-8950-100 motor. The rest of the motor does not match up though to anything that I have come across to as of yet.

Here is that 600-8950-109 next to your mystery motor ( there is a slight difference in camera angles):

And finally, adding a 622-109 Armature to the mix:

Now, camera angles and lenses make all the above an imperfect comparison, and I'm not sure I am convinced that a 600-8950-109 would fit in a 610-8503-100, and if there are variations in worm lengths...

The motor you have was meant for the MPC 8753 GG1. The armature shafts were made too long and holes in the truck casting needed to be drilled to clear the too long armature shaft. It will not fit anything other than the 8753. Use your Dremel with a cut-off wheel to cut to size and it will work fine.

@Chuck Sartor, I appreciate you chiming in! It looks like I was pretty much spot on then in my first response stating it looks like a 622-100/610-8503-100 with the 600-8753-125 armature. I did not know the '77 GG1 was the only locomotive to use that armature (I wasn't even alive then!)

@Chuck Sartor and @bmoran4, thank you both! I felt like here was something unusual about this armature/motor combo. It didn't make sense for Lionel to use the longer shaft unless there was a motor casing design change ... or an accident And the cutoff wheel gets put to work again!

George