Hi Dick,
I've not heard of this for model railroading? I do know using Google Earth images is quite popular with the Train Simulator community. It is a is very handy tool for rail, road and building placements in the Simulator environment.
To capture a Google Earth image is pretty straight forward, copy the image in Google Earth then paste into your favorite editing program. I use Corel Paint Shop.
Basically type a location in the Fly To box and click on the magnifier glass symbol to start the search. When Google Earth flies to your location, Adjust the viewing height, on my mouse I can use the center wheel to change the camera elevation, next select Edit from the drop down menu, then select copy image. Open your editing program and select paste.
The part you'll have to figure out by trail and error is what elevation you need for the scale you are working in, then send the image to your printer.