Trainz Ultimate Collection isn't really a game per se, and it isn't even really a train simulator either. It is more of a train set simulator, although Auran calls it a Railroad Simulator. The layouts that come with the simulation do not seem to represent any actual land masses, although they are all associated with countries like Germany or the United States. But they are quite small, and are really just examples for you to use as a basis for your own layouts, or to pick through so you can learn how to create layouts. And using the included tools to build your own layouts is as much, if not more, a part of the 'game' as running the trains is.
Trainz Ultimate Collection includes three modules: 'My Collection', 'Driver', and 'Surveyor'. It also includes several new utilities: 'Trainz Paint Shed', 'Trainz Content Manager', 'Trainz Content Dispatcher', 'Trainz Foundry', 'Trainz Asset Creation Studio', and the 3D modeling package 'gmax'. Two online resources are also available, 'Trainz Download Station', and 'Trainz Exchange', the latter actually integrated into the main user interface.
The 'My Collection' module allows you to look at each train car in detail, viewing it from any angle, zooming in or out to get a better look, as well as viewing information on the car itself. 'Driver' allows you to select a layout as well as one or more consists, and actually drive the trains. 'Surveyor', which for most people is the real heart of the simulation, offers a set of tools to create your own layouts, and includes an extensive collection of textures, buildings, and other items from Australia, Great Britain, and other countries.
A typical 'Driver' session involves assembling a consist from the 130 engines and cars available, which is a simple point and click affair. You can include whatever mix of train cars you wish to, and you can create multiple consists, placing each one at a different track mark in the layout. You also have to choose a layout, and there are several more to choose from than the original Trainz. Finally, you load the layout and take control of the train.
If you've created a closed layout that doesn't require any management, you only have to crank up the trains' speed, and then watch them run using the various camera views available. But if you are using one of the supplied layouts that isn't an enclosed track, or you've created one with junctions, signals, and portions of track that allow trains to derail, you will have to spend more time managing your trains.
Besides the new content, the other major addition is 'Trainz Paint Shed', which was originally available separately. This program allows you to take any locomotive and repaint it, place photographs on it, and more. Most of the remaining utilities were already available as downloads from the Auran web site, although some are new, but they are all for those who are interested in creating their own content, which might be out of the realm of interest for casual gamers.