Yes Stewart, good point!
For others, just because a tourist railroad may have a "public road crossing", only minimal FRA regulations would apply, such as monthly injury/illness reporting and basic passenger hours of service. If the railroad has a steam locomotives, bridges and active warning at crossings, then those FRA regulations would apply. As Stewart pointed out, some of this is already a part of an "insular" system and are good minimum standards to follow anyway. In most cases, the addition of a public road crossing would not be a heavy lift.
MDR