The feds have a map with all the big railroads on it. At high zoom levels, it only shows lines that have Amtrak trains, but keep zooming in and it'll show all of the freight railroads too. No frequencies, but it does have the mileposts, and some of the station/siding/junction names.
https://fragis.fra.dot.gov/GISFRASafety/
For UP only, a (now retired) engineer posted his own versions of track charts for most of UP's system. Archive at
http://web.archive.org/web/20160330215920/http://fogchart.com/FOGCHARTED.htm . Not all of them have radio information, but they do have the mileposts, station names, etc, that might be interesting. (The radio information on those charts is usually the AAR channel number, and not the frequency, but you can look it up.)
BNSF apparently doesn't mind about having their employee timetables online, as long as they are at least 10 years old. These will have the radio frequencies as AAR channels, station names, mileposts, and other goodies. There isn't any BNSF real close to you, but if you're interested, see
BNSF Timetables – Phase 4 – FOBNR.ORG .
