That's excellent work, love the loco detail. The cab detail is also very good and is about the most difficult part of the modelling, IMO. The MSTS graphics engine is very picky about high poly models, hence the 'closed' windows on the C16's cab, because the BB is already approx 20,237 polys without any interior 3d detailing.
I have always liked the Auran sim from a scenery perspective, with great looking results possible, although the steam train physics let it down. I know the graphics engine is quite flexible, allowing highly 3d detailed models, compared to old creaky 1997 vintage engine of MSTS.