A quote from Pwares thread........
From memory it took several months to create the landform contours in Trainz (TS12 it was back then) for the 47 mile (75 km) line and surrounding baseboards in the Fingal Line. It was not a copy/paste from Google Earth I used but a very slow and tedious method involving measuring out a grid pattern on the Google Earth images and recording the heights along the grid lines, then reproducing the same grid lines and heights with track splines on the Trainz layout and bringing up the terrain to match the height. I will not be using this method again - life is too short.
The program I will be using for my next project will probably be TransDEM, a commercial (or payware) program and is available at
http://www.rolandziegler.de/StreckeU...ansDEMEngl.htm but be warned, it is a very complex program. It can take data from a number of different sources, such as satellite mapping services, and convert it into a Trainz layout, complete with track if you want. I used it some time ago and succeeded in getting it to create a small layout for me but it takes a lot of time and practise to master. There are some excellent tutorials at the web site (above) but you need to have the time to work through them.
But no matter which method you use, an accurate layout of a real train line takes a lot of time, and the longer the line the longer it takes. Then you have to add the ground textures and the scenery to make it look as authentic as possible - that can take as long as modelling the landforms.