SAN FRANCISCO (KCBS/KPIX 5) – Bay Area Rapid Transit workers embroiled in contentious labor negotiations were voting Tuesday on whether to authorize a strike when their current contract expires Sunday night.

The two major unions representing 2,375 BART employees planned to release the results of the strike vote on Wednesday.

The Metropolitan Transportation Commission, which posted an alert on its 511.org website warning of a potential BART strike come Monday, said it was putting together a contingency plan that included using extra San Francisco Municipal Railway buses, light-rail vehicles and ferry service.