TC3 is struggling performance wise in places with the default textures etc. used, so JVC style grass would probably have brought it to its knees!
And why should that be? KRS has
3D trees and foliage, i dont think that some grass should kill FPS, a prime example of why the whole graphics engine needs a complete replacement.
The sounds in KRS are awful. None of the diesels sound much like their respective prototypes and there is no attempt to distinguish between the sounds heard outside the train or on the inside. KRS track sound is a disembodied tinkle - contrast with the full bodied "crunch" as you go through a set of points in TC3.
This is true, with the exception of the Deltic and somewhat of the 166, the default sounds were a joke, thankfully thats what third party creators are for.

CHeck out these new Valenta HST sounds if you dont believe me
http://www.youtube.com/watch?v=0HUR4ZsabyI
Track sounds can also be customized and you can have different track sounds on different sections of track.
The graphics in KRS are not that much improved over MSTS and TRS. Certainly nothing like the early "photo-realistic" mock up shots they were still showing on their website up to release. A few trees with leaves on them do not make a better train sim and TRS can do that anyway, with the many excellent and detailed trees, grasses and shrubs now available. The game engine appears to have been cloned from MSTS, if the frequent pause and stutter for loading are anything to go by.
Do MSTS and TRS have shaders? nope. Dynamic weather? MSTS, no, TRS, somewhat. Does the water in either of them reflect objects? no
The game engine obviously has some similaritys to MSTS as it was made by the same developer, kinda like how all the TRS series have used the same Jet engine since Trainz 1.3
You contradict yourself when you mention grass and foliage, if using all that detailed grass would bring TRS to its knees, then whats the use of having it other than to make pretty screenshots, (which is all i ussualy ended up doing..)
KRS physics are not too bad, but when you hit a train coupling up at 6 MPH the wagons and coaches should not fly up in the air. However their answer to a rather poor implementation of dynamic cab and suspension movement was to simply remove it in SP1, rather than fix it.
At 6 MPH i will assure you the wagons dont fly up into the air, actually when you make a coupling aroun 5- 10 MPH the wagons wildly sway to the side but stay on the rails, it seems quite realistic to me. If you go over 15, thats ussualy where things start to get ugly, unlike in TRS where you can couple at 60 MPH and everything is fine and dandy.
KRS signalling and AI despatching is a mess though maybe an outside chance it's about to be sorted in SP2. Yes, TRS desperately needs an AI signaller and the ability to run timetabled scenarios but at least for now you can intervene and get things moving. Prior to release, EA/Kuju were advertising RS as a simulation of such high standard the real railway companies might want to use it, then one of the first activities people tried had trains running red signals outside Paddington and emulating a very real serious rail accident that happened a few years ago.
What can i say the RS signaling and scneario system is a mess, i havnt had too much luck with it, my main issue when creating a scneario is it is impossible to change the automatic switches manually. I never had much luck in TRS either, in the one scenario i made my AI switcher kept on derailing for no apparent reason when i told it to go pick up a boxcar, i will still admit though the TRS scenario editor is better.
Didn't want to turn this into an anti-RS rant (again) but it is lacking as a serious simulation despite the NuLabor style spin being applied on other forums for fear of upsetting the devs (hush, they might not post again...). Tragic.
Really ive heard enough of this UKTS fanboy talk, do you really think this forum is any better that you guys are nothing but TRS fanboys yourself especially when you get post like:
TTTTTTTTTTTRRRRRRRRRRRRRAAAAAAAAAAAAAAAIIIIIIIIIIIIIIIINNNNNNNNNNNNNZZZZZZZZZZZZZ!!!
But instead everyone at UKTS gets dubbed as a "Fanboy" because they are actually trying to create content and improve the sim instead of sitting around and bitching and moaning about all the problems?