This bug is somewhat hard to see... but once you've seen it, you can't unsee it. Take a look at the left corner of the windscreen on the Class 45 next time you drive it. There are weird transparent streaks (or lines) of colour bleed running down it. Easier to spot when the train is actually moving.
Unfortunately i already had motion blur switched off when i took the screen shot. So it won't fix this bug.
I do believe this is caused by turning motion blur off. I guess that those fragments are part of what makes motion blur work. Also you can find this bug (if it is a bug) absolutely everywhere, every single loco and wagon has this :C
Erf, So motion blur on = flickering window surrounds and other nonsense. And motion blur off = Other types of graphical issues. That's realy sad news. :c