I copypaste here some text from this
http://www.railsimulator.com/microsite_ts2012/assets_microsite/faq.pdf
1-Multiple-source dynamic lightning: allows streetlights & headlights to illuminate the ground and nearby objects
2-Extended terrain draw distance and terrain shadows
3-Multiple-headed consists to allow consists to be powered by different types of traction
4-Particle effects on locomotive windows -e.g. rain drops
5-Working vipers which clear away rain drops
6-Improved skies with stars and moving clouds
7-Water with depth and reflections of nearby objects and terrain
8-Depth of field can be switched on to give a camera focus effect
9-Soft shadows mimic real daylight shadows
12-Consist speed limits realistically enforced
11-Improved track unevenness and cab camera movement increasing with speed
12-Smoothing of vertical curves on tracks
13-New, user interface and loading screens
14-Superelevation creates accurate simulation of curved tracks
And Hert, does trainz really have all of these?
I added number for clarity. Bolded ones we have (explained below).
#2: TS10 & 12 "extended" the draw distance. however just saying you "extended it" doesn't say much, they could have added an extra foot of draw distance for all we know.
#3: If I'm reading this right, it's saying you can have multipul engines pulling a train. We have been able to do this since day 1.
#6: Again "Improved Skies" doesn't say much. However we have had moving clouds since day 1 as well.
#7: we have water with depth, just lacking the reflections.
#9: Shadows in TRS are primarily done by the modeler (and now by others with PEV's QuickShadows) they vary from object to object, but overall I'd say are pretty realisitc.
#12: I'm not entirely sure what this means. It either means that you cannot surpass the speed limit (which is unrealistic, and would detract from their claim of being the most realistic) or they are sayin AI doesn't. Which Trainz has.
#13: new GUI, whoopee, our TS12 has a new GUI.
#14: can be done in Trainz, there are a couple different Superelevated track sets out there & banking consists rules as well.
so more 50% we have in TRS, many having been in for for ages. I'm not really impressed.
I'd also point out that the screenshots aren't that impressive either in my opinion. The track looks similar to old UTC-era track, the buildings look very 'flat', Engines & Rolling stock look on-par with what we have currently; if not somewhat dumbed-down, I've never been a fan of the RW/S trees. I'd list more, if there were more screenshots. Overall based off the pictures on their site, I would say they are about on par with Trainz 2009.
peter
Edit: I'd like to add that our Surveyor is generally considered to be easier to use then RW/S, and our AI is a more in-depth system. RSC did mention in the FAQ that they've made improvements to their route builder, but I still don't think it will be up to par with N3V's. Oh also Custom content, there is way more great custom 3rd part content for TRS then there ever will be for RW/S because you basically end up having to hack the game (so I'm told, never tried it). Oh & most of ours is (technically) free.