[Lynn Eades]

Agree with Rob. Clean it up and see what you have left. Then find an appropriate die nut to run down it. Then if it is not enough thread to make you happy, press the stub axle out using heat , while supporting the casting in close to the flange of the stub axle.(there is enough meat in the casting if you find a nice fitting piece of steel tube that just goes over the axle)
I cut a bad housing to get a good stub axle out, but then needed to get a bad axle out of a good casting with a bit of time to soak in some penetrating oil and a bit of heat it came out fairly easily. (in a press)
Your LP1 adjusting plate looks to be exactly the same as an early U.C (British and Canadian) and same as mine.
We had a thread on here that talked about the thread of the bogie axles.
This axle is the same size as the nuts are the same for all locations.
If you take the axle out, you can have it built up and a new thread cut on it or you could go down a size, which would require a dedicated nut and a special washer with a smaller bore.