Found HERE. If the information on Wikipedia is correct about copyright issues, and New Zealand copyrights expire after 50 years, then this should now be under public domain. (See date under the signature on the bottom right - 1929)
Woo! This will do just fine in helping me build the locomotive. It's hardly a detailed picture, but I should be able to use it to do one of my scaled drawings. That should come in the next day or two.
I'd still like some photos, though, so I can see all the details not listed here (and I know of at least a few).