Welcome to, as Ben says, this wacky world of Trainz.
As a longtime route builder, there's a couple of things you might want to try.
Before you dive headlong into a new route, I recommend downloading a small one from the DLS and editing it. Use the opportunity to see what people have done, add your own textures, add a baseboard or two, makes some hills, valleys, plop in a bridge, a tunnel or two, and so on. This will not only let you try the tools of the trade it will also give you a chance to see how it's done. I did this over a decade ago and I've been at it ever since.
When you are ready to venture into the real prototypical routes, and if you are using a PC, I highly recommend investing in TransDEM. This is a $30, roughly, program available here.
http://www.rolandziegler.de/StreckeUndLandschaft/startseiteTransDEMEngl.htm
With TransDEM you can import digital elevation information from areas around the globe, but more specifically for you from the National Geologic Survey (NGS) map server. Combine the DEM for the area you are working with, along with some historic topographic maps, and you'll have the routes marked out ready for laying tracks on. The best thing with this program is it will put the historic maps right into place on the DEM. There a is little fiddling needed to get this to work, and there is a bit of a learning curve, but it represents a whole new dimension to route building. This works even for freelance building as well because these files are fully editable in Trainz just like you added the baseboards yourself. I have taken actual DEM files and maps, and have put railroads where none ever ran.
But, before you make this giant step, try a baseboard or two as that will give you a chance to work up to a bigger project. Just like model railroading, the great ambitious plans that come out of that pile of spaghetti on plywood also happens virtually. With big projects, you can easily tire of placing track, buildings, grass, and so on for miles upon miles to fill a huge route. The good news with this is you can go about this process a few times without throwing anything away except for your time and a few electrons from your computer unlike a real model railroad where we can spend a lot on track, plaster, and plywood only to scrap it later - been there and done that a few times in my life on both accounts.
The other good thing too about virtual modeling is you can take what you've already done, if you like it enough to keep it and add that to another route or section. When I built my first route in December 2003, I started with 4 baseboards. Out of that original section grew a small empire, which got upgraded and changed a few times along the way. The original route is still tucked away on DVD/CD somewhere, and the second iteration became the seed of the current I'm working on today.
Anyway, Don't be afraid to ask questions and feel free to post in the appropriate sections of the forum, such as the Surveyor and Operations for questions on how to do stuff. We will assist you with your new virtual world.
John
