Sage advice, Allan.
There is a live steam club (small scale and a range of larger gauges) in my vicinity that I plan to check out this summer, perhaps find a mentor and ask lots of questions. I'm taking my time and it's entirely possible I'll decide that coal firing is prohibitively expensive.
Thanks!
Make sure coal fired is what you really want. Anything smaller than 3.5'' is very difficult to keep alight and can be a real pain. Don't forget coal is just an alternative to gas firing at a considerably higher cost. some people even go back to gas......Allan.