In an instance of a rail fixed guideway public transportation system that operates in more than one State, all States in which that rail fixed guideway public transportation system operates must either:

(a) Ensure that uniform safety standards and procedures in compliance with 49 U.S.C. 5329 are applied to that rail fixed guideway public transportation system, through an SSO program that has been approved by the Administrator; or

(b) Designate a single entity that meets the requirements for an SSOA to serve as the SSOA for that rail fixed guideway public transportation system, through an SSO program that has been approved by the Administrator.