The old rec.aviation.soaring, which is still searchable, has a number of threads on replacing ALKO axles. Here is one with a couple of suggestions (perhaps ship Euro axle with new glider trailer; North American source for replacement):
For added historical value, you can see posts after the useful stuff that reminds us why RAS_Prime is so much better.
Old RAS still has valuable info (or at least opinion) and shouldn't be forgotten.
Dan