Cal. Pub. Util. Code § 125452

A violation of any ordinance, rule, or regulation enacted by the board prohibiting unauthorized operation or manipulation of transit facilities owned or controlled by the board, or prohibiting unauthorized tampering or interference with, or loitering in or about, transit facilities owned or controlled by the board, is an infraction punishable by a fine not exceeding seventy-five dollars ($75), except that a violation by a person, after the first conviction under this section, is a misdemeanor punishable by a fine not exceeding five hundred dollars ($500) or by imprisonment in the county jail not exceeding six months, or by both that fine and imprisonment.