I think we ran Traincraft before… it doesn’t play well with some of our mods (I wish I could remember which ones off the top of my head). Additionally, I think it generates some ores (oil sand and such)… which would mean another mining world.
Let me stabilize 0.81 first and I’ll take a hard look at it.
To be honest, I’m not sure if it works with our current mods (Railcraft/Steve’s Carts/Mystcraft specifically… although it’s possible
To add a mod, simply install a new instance of the pack… browse to the instance folder, and drop the mod in the “mods” folder. You may hit into block ID issues. Thankfully, NEI catches these (usually) and will make a file (as well as tell you where it is) saying which blocks are conflicting and what IDs are available. Then it’s a matter of editing the offending config to fix it (it will give you two configs, only edit the most recently added one…)
There’s usually item conflicts/overwrites that do not get caught by NEI which require searching the ForgeMod log for.