Cal. Pub. Util. Code § 90601
Whenever the board by resolution passed by vote of two-thirds of all its members determines that the public interest or necessity demands the acquisition, construction, or completion by the district of any transit facilities or any works, lands, structures, rights, equipment, or other property necessary or convenient to carry out the objects, purposes, or powers of the district, the cost of which will be too great to be paid out of the ordinary annual income and revenue of the district, it may at any subsequent meeting of the board provide by ordinance for the submission of the proposition of incurring a bonded indebtedness for the purpose set forth in the resolution to the voters of the district at a special bond election held for that purpose.
Ca. Pub. Util. Code § 90601