I understand why the FRA man would check switches. But like you said most tourist lines run only one train.
If the state did not do their job well, and a serious accident happened with a boiler, I contend the FRA would step in. They would probably be pressured to step in and perhaps take over. My believe is, like I said earlier, their rules state what they shall do, not what they may do if they so choose for whatever reason. I may be wrong on this point. They ignored SVRy for many years ( although they told us they had authority and would someday pay us a visit, and they finally did so), and we were inspected annually by the state boiler inspector. When the FRA decided to exert their authority, the state inspector was informed he was no longer needed. Plus the FRA inspects our track, equipment, crossing signals and records. So far we have remained on their good side and intend to keep it that way.
dan