As always, our memories tend to be very short and rose tinted. If you can, look back at the posts in these forums about TANE in the first year (or perhaps longer) after its release. Red Hot flames is not quite accurate enough! Bugs, crashes to the desktop, disappearing consists and disappearing baseboards to name just a few. TANE was unstable and was not fit for release - but that is another long story. TANE SP4 is now stable but it took a long road to get there!
TRS19 SP1 and TRS19 Platinum are the most stable versions of Trainz that I can recall owning but I confess that my memory may also be short and rose tinted as well. I still keep TANE on my system purely for nostalgia but almost never use it any more. One day it will join TS12 and all its predecessors in the great byte bucket.