So now, both sides are squaring-off over the union's proposal to save money by changing retirement medical benefits.
Both sides are behaving as if it's a foregone conclusion that SEIU, BART's largest union, will reject the contract when it votes on Thursday. Negotiations are expected to resume next week, with retirement medical benefits getting top billing.
The unions say changing the eligibility requirement for lifetime medical benefits from five to 15 years will achieve the savings BART is seeking.
And they say they've talked to the benefit administrator, CALPERS, who says it can be done.
"I was in the room on the phone with the administrator, with CALPERS, the management team on the phone on a conference call. We asked 'can this be done,' and they said absolutely yes," said Jesse Hunt from ATU Local 1555.
But BART says the union's math is off, the savings are inflated and the 15-year eligibility plan is simply not allowed.
"Quite frankly it fails to address the imminent fiscal crisis that BART faces and under current state law, this plan can't be implemented," said BART spokesperson Linton Johnson.
"BART's spokesperson wasn't in on that conversation, he's not at the table, we are. We know what's been discussed," said Hunt.
A lawyer familiar with CALPERS says he believes BART and its unions should be allowed to negotiate whatever eligibility term they wants.
"We can agree for the 15-year term to be the new benchmark, that's fine, we can do that across the table. But in order to implement we have to have the law changed because CALPERS doesn't allow for a 15-year plan under current state law. Doing that could take years," said Johnson.
ABC7 tried to get some answers today from CALPERS, but they were unable to provide us with clarification.
BART is trying to save $100 million over four years through union concessions. The unions have been working without a contract since July 1st.