A California Supreme Court decision Thursday could help speed up construction of a $64 billion bullet train between Los Angeles and San Francisco by allowing the project to sidestep a strict environmental law.

The court will decide whether state-owned and state-funded rail lines are subject to the California Environmental Quality Act or whether federal law trumps it. The ruling will come in a lawsuit that challenged plans to introduce freight trains on a Northern California rail line.

Supporters and critics of the state's proposed high-speed rail system say the decision could apply to the bullet train.

The ambitious project has faced numerous lawsuits alleging violations of state environmental law. Those lawsuits could disappear if the California justices rule that federal law supersedes state law for rail projects.

The California High-Speed Rail Authority also could be freed from a host of regulatory and procedural requirements that might slow construction of the line. The project would still be subject to the National Environmental Policy Act, but critics say that's not a substitute for the state's stricter environmental protections.