I wrote StopGap for Trainz 1.3/TRS2004+, and after that Mike over at TPR wrote Scenario Creation System for later versions of Trainz, but I don't think that there's anything like that for TS2012/T:ANE.
There are so many rules and driver commands available now, that you can do most things in a session that you'd previously have to do with Trainzscript.
Whether they work correctly in T:ANE is another thing.
My Weather Control rule doesn't display the raindrops on the screen in TS12, like it used to in previous versions, so you need to be careful when downloading rules and driver commands.
Brian.