Contracts for protective services against heat or cold, provided to or on behalf of rail carriers and express companies, are exempt from the requirements of 49 U.S.C. 11105. Nothing in this exemption shall be construed to affect our jurisdiction under section 10505 or our ability to enforce this decision or any subsequent decision made under authority of this exemption section. This exemption shall remain in effect, unless modified or revoked by a subsequent order of this Board.