California Code, Public Utilities Code - PUC § 99153

Any transit district or operator may adopt uniform standards to rate bidders, on the basis of questionnaires and required statements, with respect to contracts for railroad rolling stock upon which each bidder is qualified to bid.  Notwithstanding any other provision of law, the district or operator may limit bidding and award of contracts for railroad rolling stock to the bidders the district or operator has determined are qualified to bid.  However, the district or operator shall qualify at least two persons or entities for bidding on the contracts.