Haven't heard of anything like that. (come to think of it, I hadn't heard of RailPlanner until you mentioned it...)
I always check the trains on
www.traintimes.org.uk before I travel. Doesn't use any other software apart from the browser, and it gives a good clear run-down of the information needed.
Train maps are also available online if you need them.
If you need more than that, I'm not sure what to suggest. What features of Railplanner are you particularly interested in? It's always possible that RailPlanner might work in Linux under Wine; but you'd need to actually try it to be sure of that.