Hi, there is a guy called mike who made stuff back in the day. but after that he started to sell stuff. Sorry but if you want to do nzr you will need to give him some money.
on the download station do a search for nzr, nzgr, kiwi and zealand that will find some cool loco's etc
NZRailfan user name will give you lots of free stuff to build your own
PS make sure you tick 2004 even beter tick everything