First, good luck in your applications!
Second, to answer your Trainz question, this is sort of the deal with the 2:
TS2010: Works with basically everything out there, is older an by extension cheaper (I got mine from Topics Entertainment or something from Amazon for $20 a few months ago, and it seems totally fine and I haven't had any issues!). It has the SpeedTree capability as well as most of the core stuff TS12 has, minus Doppler sounds, satellite view, and perhaps some others. It comes with around 30 routes, and plenty of content on the disk, but most of this IS older, so bear that in mind if you are looking for all the brand new, HD stuff on this forum. Also, has compatibility mode for content that has basic errors in newer games, although most content can be fixed to work fine to new standards.
TS2012: Does not include any older content, but includes some excellent content and routes that are much newer. As well as the content and the couple of new core game features (Doppler, satellite view, extended draw distances, etc), I have heard a lot of people praise TS12 for performing better on their computers then 2010 or earlier. I can't confirm this myself as I do not currently own TS12 (because I have 2010, I have not quite yet felt the need to spend another $50 on games. I will probably get it in a few months, or if I see it at a cheap price on sale).
Sorry I can't give you an actual answer, but hopefully this will help sum up the differences. Be aware I have probably missed some things, so waiting for some other input may be wise.
-tyard