Recently there have been a slew of posts on various forums around the internet about split gears, and as it seems to have been a 20+ year issue, no doubt they will continue.
I recently chatted with a guy who had a 4-6-0 but it turned out not to have the current wheel design - his wheels were pushed on to the axle using the plastic of the spokes as insulator. (Later versions have a screw holding the wheel on to the axle.)
Turns out the ‘Indie’ 2-4-2 also has that design, as they are from the same period. (I have no idea what they used on the 2-6-0 re-make.) You need a 4" vise or larger, a hammer and something like a crowbar. Plus the usual small tools to unscrew the frame and get the wheels out.
As you can see, there is a plastic insulator in the hub that is pushed on to the axle. You can also see that I marked the axle with a dab of black paint to show where the crank pin goes. Both axles have to be the same, and you need to mark both ends of the axle with the crank location as you don’t know which wheel is coming off. A quick rub with a file will leave a mark.
and as you can see, the gear is cracked and can move anywhere it likes.
This chassis is a relatively new one - earlier versions have a pair of wipers sprung against the wheels instead of these pistons. But it shows how you get the wheels and axles out. Once you have removed the 2 screws under the cab, and the deeply-recessed screw under the front smokebox, you can release the 2 screws holding the chassis cover and the wheels drop.
Now you have the axle out, put it in your vise with the plastic hub resting on the jaws, (don’t just support the metal spoked area,) like this:
(I’d actually removed the wheel by this time, so I pushed it back to take the pic. It shouldn’t be as wonky as that!)
Tighten the vise to the axle lightly so it stays where you want it, then rest the crowbar on the bottom plastic hub:
Give it a good bang with the hammer, and move the crowbar to a new position each time you bang. Mine came off with just a couple of thumps. And there you are - once off, the gear falls off. In this pic I have a new Delrin gear from Jerry Yeramian ready to go.
Here’s the driver without the axle.
To get the gear on and the wheel back, you need to tap the wheel with a piece of wood (to prevent damage to the paint) on the hub. You slide Jerry’s gear on to the axle, insert the axle into the vise with the gear on top of the jaws, and tap it in the vice until it is centered on the splines. Then do the same with the other wheel.
And you are done! Just put it all back together carefully with a little grease in the gears and axles.
P.S. I do not think Jerry Y has been asked to make a Delrin gear for the 4-6-0 yet. I know there are split ones out there. . .
