(a) General Severability. If any part or any application of any part of this Locomotive Regulation is held invalid or otherwise unenforceable by any court of competent jurisdiction, such part(s) or application(s) shall be deemed separate, distinct, and independent of other parts or applications of this Locomotive Regulation, and such holding shall not affect the validity and enforceability of the remaining parts or applications of this Locomotive Regulation, except as provided in subsections (b) and (c).

(b) Alternative Compliance Plan Severability. If the part(s) or application(s) held invalid and unenforceable affect the obligations of a Locomotive Operator with an approved ACP, the affected ACP shall no longer require the Locomotive Operator to achieve equivalent emission reductions for the invalidated part(s) or application(s). Thus, the Locomotive Operator would no longer be responsible for any portion of that ACP solely devoted to achieving equivalent or greater emission reductions than would have been required by the invalidated part(s) or application(s). The Locomotive Operator would continue to be responsible for all other portions of the ACP. If a portion of an ACP is devoted in part, but not wholly, to achieving equivalent emission reductions as would have been required by the invalidated part(s) or application(s), the Locomotive Operator would continue to be responsible for that portion of the ACP.

(c) Alternative Fleet Milestone Option Severability. If the part(s) held invalid and unenforceable include section 2478.8 (or any subprovision thereof), then all existing AFMOs automatically expire as of the date the court's judgment becomes final, or if subject to appeal, the date on which any opportunity to appeal expires or the date on which final judgment on appeal issues, whichever is later. If the application(s) held invalid and unenforceable include application of section 2478.8 (or any subprovision thereof) to one or more Locomotive Operators, any existing AFMO applicable to those Locomotive Operators automatically expires as of the date the court's holding becomes final. The invalidation of any part or application of any part other than section 2478.8 (or any subprovision thereof) has no effect on the requirements of any AFMO, and those requirements remain in effect.