[Code of Federal Regulations] [Title 30, Volume 1] [Revised as of July 1, 2006] From the U.S. Government Printing Office via GPO Access [CITE: 30CFR36.28] [Page 184-185] TITLE 30--MINERAL RESOURCES CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR PART 36_APPROVAL REQUIREMENTS FOR PERMISSIBLE MOBILE DIESEL-POWERED TRANSPORTATION EQUIPMENT--Table of Contents Subpart B_Construction and Design Requirements Sec. 36.28 Signal or warning device. All mobile diesel-powered transportation equipment shall be provided with a bell, horn, or other suitable [[Page 185]] warning device convenient to the operator. Warning devices shall be operated manually or pneumatically.