"Under Federal Law" ???? Not the case here. This is a maintenance operation and many railroad permit track cars operations without any charge. In most cases the operators are qualified on the rules, had their annual test, spent a day in the annual class of "on track safety rules". and with the signing of a release, receipt of form D or track permit-out you go. Federal law also do not now and never had covered the steam boilers of rotary snow plows, pile drivers or other steam boilers in M/W service. Some states show interest but they legally have no authority over the railroad in interstate common carrier service. Only Federal jurisdiction covers that.
Same is the fact that only a Federal Marshall has the right to enter a locomotive cab and every Town Cop or State Officer or Trooper is "out of jurisdiction" if he goes into a locomotive cab or on a locomotive. I for one run every two weeks in summer on just a work/ride on a railroad by arrangement, and pay with sweat.