"I think we need to have solid car plan now, and I don't see it yet." Raburn said. "Do we order 700 cars, 1,000 cars, or can we afford 1,200 cars to improve our service?"
When to go before voters is another question.
The November 2012 ballot might seem like an opportune time because presidential elections draw large voter turnouts, which can improve the chances of passage for tax or fee measures.
BART officials, however, are concerned the 2012 ballot could be too crowded with tax and fee measures by school districts and other agencies hurt by the state's budget problems.
Also, the Alameda County Transportation Authority plans to go to voters that election for early renewal of its half-cents sales tax for transportation.
The Metropolitan Transportation Commission also is looking into the possibility of a regional gas tax ballot measure in 2012 to fix deteriorating roads and ease public transit service cuts, said Randy Rentschler, a commission spokesman. More study must be done before any regional measure is proposed, he added.
"If the ballot is too crowded with tax measures, voters could get fed up and vote everything down," said Keller of the BART board. "But if we wait, we can't wait much longer."
The transit agency later this year is expected to select a company to design and build the train cars, which will delivered over the next eight to 10 years.