California Code, Government Code - GOV § 67541

The authority may exercise the right of eminent domain for the condemnation of real or personal property or any right or interest therein for its use within the City and County of San Francisco, including the power to acquire real property in fee simple or any lesser estate or interest or for rights-of-way or other uses of the authority and also for the purpose of protecting and preserving the rights, powers and privileges of the authority with respect to any facilities then owned or operated by the authority.  No publicly owned property shall be taken, or condemnation proceedings instituted therefor, without the consent of the public agency or public corporation owning or controlling such publicly owned property.

Notwithstanding the provisions of this section no taking or acquisition of title or possession, by the district which would involve the abandonment, removal, relocation or use of the property of a railroad corporation, as defined in Section 230 of the Public Utilities Code, shall be permitted, unless the Public Utilities Commission, after a hearing, shall find and determine that the public interest and necessity require the abandonment, removal, relocation or use of such property and that such taking or acquisition will not unreasonably impair the ability of the railroad corporation involved to provide safe, adequate, economical and efficient service.