Cal. Public Utilities Code § 105152

For a period of four years, commencing with the district’s decision to commence rail service as provided in Section 105151, or until the expiration of the current collective bargaining agreement, whichever is later, employees of the district organized pursuant to Part 3 (commencing with Section 27000) of Division 16 of the Streets and Highways Code, who are employed by that district in classifications assigned to the same or similar collective bargaining units as those set out in Section 105151, shall be given priority of employment within the collective bargaining units set forth in Section 105151. Any dispute arising over the appropriate placement within a collective bargaining unit or over any assignment of classifications made by the district to a bargaining unit set forth in Section 105151 shall be resolved by the Public Employee Relations Board. Any determination of the Public Employee Relations Board shall be consistent with the intent of this section.