If you use Trainz A New Era or TRS19, these sessions and routes have been made in T:ane, or if specificied in TRS 19. Some are even free. The first route I built was "The Great Zig-Zag", which has already been downloaded from the N3V (Auran) site over 2,600 times in less than 2 years. Very soon to be released (any day if not already) is the new route, Bathurst to Lithgow (NSW), which extends from the first route. I am constantly creating new sessions, and there are a few sound files of Australian birds, from my own recording as well.
As the game itself is made by N3V (formally Auran) and not myself, I have no control over software that is their creation. No warranty is given as digital products can not be returned, and many of these are free anyway. So buyer be warned. However if you do have issues, let me know and I will attempt to sort out your problem or refer you to the Trainz Discussion Forums where you may find suitable answers.
Personally I've had Trainz A New Era for over two years. Almost immediately I began working on the Zig-Zag circa 1910 (the year it closed), and then began creating sessions, for numerous routes. Most have been made available via N3V own game DLS. I hope to make these available to more people who enjoy the game.