Notwithstanding the provisions of Article 1 (commencing with Section 105140), in order to protect and preserve the collective bargaining rights of employees of the district organized pursuant to Part 3 (commencing with Section 27000) of Division 16 of the Streets and Highways Code, whose employment opportunities may be adversely affected by the adoption and implementation of this division, upon the district’s decision to commence rail service, the district shall establish at least three collective bargaining units comprised of the following: