Now, not to start a war here, you can actually create your own route in Surveyor. Using the basic tools, you can sculpt the landscape how you like it, lay the track and landscape everything with textures, assets, and trees. The biggest issue is patience and time and working with your learning curve at the same time. In the olden days, this was the only way to create routes until people discovered data files and created tools to convert those to Trainz data. The tools do require time to learn, but they give you the base to start with which means you have the land in place ready for landscaping and track laying.
After saying that, we all recommend, I mean highly recommend, you start small. A few baseboards will do to start with, and you can always expand later. My very first home-spun route was about 4 baseboards and that is quite complex now. We also recommend opening up routes in Surveyor and looking around to see how things are constructed. When I started, I found George Fisher (gfisher) to be my virtual mentor. There are many other excellent route creators today and take a look at their methods and experiment with them. The worst thing that'll happen is you don't like the results and spent time. Once you've become experienced with this method, which will be needed many times over anyway, you can go to the next step of importing real-world data.
The data is obtained from the National Map servers run by the U.S. Geological Survey.
The National Map | U.S. Geological Survey (usgs.gov)
Be warned, it's a typical government website that's a bit more complicated to use than it should be. Once you know what you need and find it, it's not so bad. In order to bring the data into Trainz use the highly recommended TransDEM program that was created by fellow Trainz user GeoPhil. This is a payware program that costs about $26-28 bucks these days.
TransDEM (rolandziegler.de). The home page:
TransDEM (rolandziegler.de)
Yes, there is a big learning curve here, but what you'll gain here is an amazing ability to create routes from anywhere in the world. The base-export from TransDEM is a route ready for import complete with the topographic map textures in place and even UTM tiles on a layer ready for displaying if you want to go that route. You can even export a quick the route with some of your track in place ready for adjustments or leave that blank and only use the topographic map which many of us do so we can lay down abandoned lines. You can even go as far as to trim the route down, so you don't end up with only what you need. This can be tricky because you don't want to cut out the size of a hill and many of us do a basic trimming in TransDEM and finish off the closer stuff manually in Surveyor.
The only problem we have when using this method is producing routes that are bigger than we can chew! Once the route is imported into Trainz, it's no different than any other route you have installed. You can even go as far as to create a fictitious line on the same terrain and even merge this into another route. Since the route uses real world coordinates, you can even merge in additional parts to the route in the same region because they will line up. Some of us build small sections at a time and merge them together and this works well if you do a collaborative project. The only thing you need to be careful with is trimming because you want to ensure everything remains intact otherwise edges don't line up.