Mike G. uses ExpertGPS to research abandoned railroads in Northeast Pennsylvania. Here he reviews ExpertGPS as a historical map research tool:

The main reason why I tried out this program, and purchased it, is because one of my hobbies is abandoned railroad research. My area has a large network of abandoned railroads since at one time the coal industry was "king".

Looking at present day Topo maps and even ariels are limited because most of the old ROW's have been erased or are broken up by development. There is a site that has historical USGS maps which is very helpful to trace out these once busy lines, but is limited. The single most reason I purchased this program was the ability to take a historical USGS maps and integrate them and make them more GPS accurate. Already there are a few relics from a former railroad line that could not be identified until I overlayed the map onto my GPS data. I maintain a website with my findings and the example of how this program solved a mystery can be found here.