The DTMF "Switch" (Turnout) locations are not on mainlines at timetable speed. You will see that in some yards or if on mainline locations where the train stops (or otherwise verifies switchpoint location) before proceeding, as per FRA rules.
Railroad police in the USA (Excepting Amtrak) are not "Federal", they are private police agencies, with the officers receiving state authority, with jurisdiction to cross state lines in pursuance of a Railroad investigation. I haven't heard RR police in the clear in a few years now.
TSA/DHS has security interests in basically all forms of transportation, railroads included, and rightly so.
However, the FRA has "Sole jurisdiction" over rule-making and enforcement over Railroads.
And there is NXDN on the Rails, been tested in a lot of places already for coverage. Has not been implemented for transportation on road or dispatch channels yet, but on class 1's, almost all radios are now NXDN capable, and are being (if not already) programmed with analog zone and NXDN zone. (And class 2, 3, regionals and shortlines, you can get a mix of everything)
Good thing is, what I have heard, sounds really good. YMMV, as with everything.