Creating a prototypical route in Trainz is very popular and there are many means of doing so. Prototypical routes can be downloaded from the DLS and others are available as content included for distribution with Trainz, e.g. TC3 has the 1950's/60's Settle and Carlisle route included.
When attempting to create a prototypical route, it is up to the user how much detail, time and effort is put into the map, therefore affecting how representative and accurate the simulation is to be.
The initial stage of creating a prototypical route (or any prototypical asset) involves some sort of research and collection of information, e.g. maps, photos or drawings to help the creator in placing track and other objects accurately on the map. Many Trainzers make use of software such as Google Earth, Flash Earth or Microsoft's maps.live.com in order to obtain aerial information regarding their route.
Of course, to be truly accurate and representative of the actual route, the user may need to consider creating his/her own content if the DLS and other sources are not satisfactory.
An Introduction to DEM's and Their Implementation in Trainz:Edit
Baseboard maps are objects (assets) that are able to be placed on a board in Surveyor mode in Trainz. The object is a flat plane with a 1km2 map textured over it. The purpose of baseboard maps is for accuracy in placing scenery and track items in a prototypical layout. The boards are height adjustable and can be used in multiples. Once finished with the asset can be removed from the map.
Baseboard maps are available from 3rd party sites on the internet or can be easily created with Gmax and a basic knowledge of content creation. The usefulness of these items depends on the map they are textured with and how the user implements them in Trainz.