I use Delorme' Street Atlas USA with mating GPS daily. It works very well to show you where you are on the displayed map, and includes rail lines as well. But Delorme's product won't even show railroad signal locations, and certainly not their displayed aspect.

But, its possible to use ACTSMon software:
[www.atcsmonwiki.org]

to interpret coded radio traffic to/from lineside devices and update a display on a laptop that is similar to what a dispatcher might see. The ATCSMon software is developed and maintained by hobbyists, but uses published AAR specs. The RR industry could officially embrace this technology, but at this point a crew could find themselves in big trouble if they relied (exclusively) on the PC display. Since it is radio based, the laptop is fed codes from a scanner, and is subject to all the reception problems any mobile scanner has.

You could use it to see what the next signal MIGHT be, but you would have to proceed as though the signal was more restrictive than what you expect.

Of course, this would only work where the lineside devices use radio transmissions to communicate.