This may not be news to most of you, but I have just discovered Micro$oft's answer to Google Earth, and it scores a few points over its rival.
Firstly, the maps (like Google Maps) and 3D (like Google Earth) are integrated so you can switch between the two.
Secondly, and more importantly, you can switch to viewing the un-manipulated source images. Because these have not been twisted to remove the natural perspective of the shot, the whole resolution is available, providing far more detail. The upshot is that there's enough detail to make out railway features such as signals, gantries and even individual sleepers.
Here's an example :
a quiet Preston station, where a Pendolino is just visible poking out from under the canopy, and a 57/3 in the north bay (can't quite make out the number ;-) )
The down side to all this is that you need to install it on your PC (like Google Earth), but it's worth it IMHO.
Adrian