Trainz, any version for that matter, is like having a gigantic model railroad and one that you can build a layout of your dreams. There are so many things that can be done ,and as Martin says they can be as complicated as you want to make them.
With about 400,000 give or take a few assets to play with, you can spend your time downloading routes, installing assets, fiddling with them, and building a route of your dream, or even take someone else's route from the Download Station (DLS for short) and customize that to your liking including merging routes together to create a massive route.
If you are into prototypical routes, you can use a third-party application called TransDEM to import the National Geologic Survey maps and DEM data, and place these maps exactly in place on the underlying DEM. With the DEM and map in place, all that is left for you to do is lay the track and place many, many objects. You can even take such a map and rebuild routes from the past, those that have sadly been abandoned and turned into trails today, and brought back to life and even modernized if you want. Imagine reopening the old NYC Water Level Route portions which were removed during the 1950s, or rebuilding the New Haven across the Poughkeepsie Bridge, or some of the now abandoned routes in Pennsylvania or New York State once run by the Lehigh Valley and their contemporaries. These are only some idea... Right now a friend of mine is working on the Hoosac Tunnel as it was in the 1940s complete with his custom-built catenary and actual track layout at the East Portal yard, and in North Adams. Today this area is far different, but he's been researching with the help of the B&M HS, and museums in North Adams to get the details right.
Like a model railroad, you can customize content to a certain extent, and even build stuff of your own once you learn how, or already have the skills for that. To me this is like kit building and reskinning, a process of applying custom textures to models, is like painting models. You like a building, but want something laid out differently take a couple of them and but them together to build a new one. If done right, no one knows except you what's underneath. This is similar to kit bashing models on a model railroad.
You have a route and you want to expand it... Add a baseboard or two. You can even take those DEM-based routes and customize those. I love doing that because it's a combination of real life with a twist. I took the route from Bucksport Maine to North Maine Jct. and added a couple of branch lines to it. One of the lines follows the Pennobscott River to a location outside of White Haven. In real life there is no railroad there or ever was, but using a bit of Imagineering and planning, I put in a branch and no one would know unless they lived there, or I told them. On another part of the same route, I put in an abandoned branch to the Bangor Airport, and removed the airfield. Instead I put a huge lake and industrial park in the area.
Anyway, this is only a tiny portion of what can be done, it's only your imagination and computer hardware limitations that will limit what you can accomplish. Now speaking of computer hardware limitations, what are the full specs of your computer? That will determine what you need to run the latest version, and assist you with possible upgrade suggestions, or recommend which older version of Trainz your machine is capable of running.
John
