There is a provision in the contract with the Amalgamated Transit Union (ATU) that prevents workers from striking in the event of a labor dispute. The BART local union that is threatening to strike is part of the ATU.
However, there's a loophole that the union is using. The provision in the contract applies to state agencies. BART is a local agency, so its unions are exempt from the no-strike clause in the contract.
There is only one other major transportation agency in the entire country that has a loophole like this.
CA Senate Bill 423 has been introduced that would close the loophole. It needs support of the Governor and a simple majority of legislators to pass. The bill does not prevent negotiations, nor does it bias one side against the other. It just prevents the workers from going on strike, and using the treat of a strike as a negotiating tactic.
Time to write to the Governor and your state senator and assemblyperson. You can visit the City of Pleasanton website for details on how to contact these representatives.