One thing at a time here. If this is a first-time project, start really, really small and work on some made up things first. They can be a baseboard or two in size and these will give you a chance to learn the tools and experiment with how they work. Once you have confidence with the tools, you can then take on a much larger project.
Creating a route such as this, depending upon how detailed and realistic you want to make it, can take a very long time to complete. You will need to research the area, take pictures, look at maps and plan on creating those special items that can't be substituted with off the DLS or some other website items. To create the specific assets, you need to learn Blender to create the models, and learn a texturing program such as Gimp or Paint.net for your textures and images such as the signs. There may be trams like that already somewhere but I've never seen them. That means you'll have to create those, or substitute something that looks close enough.
For the actual route, I recommend using ordinance maps to know where the tracks and streets are supposed to go. There are a couple of methods to bring the maps into Trainz. One is using simple 720 x 720 or 1024 x 1024 images placed on assets that are locked in place. You then put the tracks and buildings and use the height information on the map to raise or lower the landscape to match. The alternative is to use a third-party program called TransDEM which is a complex program to learn but worth the time. With TransDEM, you can import the ordinance maps and place them on top of actual DEM-data giving you the actual heights of the land with the maps in place.
