30 C.F.R. § 56.9104 Railroad crossings.
Title 30 - Mineral Resources
Designated railroad crossings shall be posted with warning signs or signals, or shall be guarded when trains are passing. These crossings shall also be planked or filled between the rails.
Title 30: Mineral Resources
PART 56—SAFETY AND HEALTH STANDARDS—SURFACE METAL AND NONMETAL MINES
Subpart H—Loading, Hauling, and Dumping
Traffic Safety
§ 56.9104 Railroad crossings.

