I couldn't find the old website for the publisher; it was maybe a company circling the drain.
Your best bet is probably eBay. Between that source and swap meets (and with some patience), you could probably pick up any and every edition from 1989 to the end.
Good hunting!
EDIT Here's the publisher's street address:
Railmodel Journal
2403 Champa St
Denver, CO 80205
(303) 296-1600