There may still be a limit to the number of textures you can use. In TRS2004 I found that limit. I think it was 255, but not sure. Don't know if there is a limit in 2006.
Only issue I can find so far in route size in 06 is the time it takes to save your route.
Doesn't bother me though. By the time it gets too slow to bear, I'll we working with a new system <g>
I don't see any end to my current route. I will just keep adding sections as needed.
One 'mistake' I might have made is to fill in the empty spaces in my route, rather than leave openings in the layout as would be done in true life.
It takes more disk space, and requires me to develop a lot more terrain!
But it's all so much fun it doesn't matter how big or how long it takes.
If I had only one piece of software on my computer, it would be Trainz 2006!
FW