NORTH BAY -- Election officials in Sonoma County have completed an initial count of 5,471 signatures submitted today in support of a ballot measure to overturn the quarter-cent sales tax voters approved in 2008 to fund construction of a North Bay commuter rail project.

Staff at the Marin County Registrar of Voters office will conduct an informal count on Monday. RepealSMART, the group spearheading the repeal, submitted the signatures hours before an end-of-the-day deadline and six months after their efforts officially began in August.

Questions persist about the threshold necessary to put the repeal of  Measure Q before voters in November. Officials from Sonoma Marin Area Rail Transit contend that 39,000 signatures are necessary, while RepealSMART cites state Proposition 218 in arguing for a lower threshold of 15,000.

Clay Mitchell, co-chairman of RepealSMART, was among the people accepting last-minute signatures this afternoon.

“We don’t have an exact count,” he said. “We’re somewhere right around the 15,000 mark.”

If the initial count surpasses 15,000 -- 5 percent of residents in each county -- each registrar will then begin the more lengthy process of verifying that each signature matches a resident. The SMART board of directors will then determine if the number of signatures is sufficient for an election.

 “If they don’t have at least 5 percent, then it automatically fails,” said Melvin Briones, assistant registrar in Marin County.

Yet Mr. Mitchell said that he and other repeal supporters take issue with the SMART board’s role in the election. They claim the board would be unlikely to support the lower number of signatures and and is among the agencies that have confounded their efforts through unclear requirements.

He said that RepealSMART would be filing a notice of intent to collect signatures for a new, identical ballot measure “in the next few days.”

“It allows us to start over, basically,” he said. “This at least holds that door open.”

Mr. Mitchell also said “there has been some discussion” of suing SMART over the signature-threshold issue, though they have no current plans for legal action.

“With this cloud of legal questions, we don’t think there’s a chance to get a fair shake at this,” he said, claiming a lack of direction from election officials. “It should be clear, ‘This is the law. You either pass or you fail.’ ”

SMART General Manager Farhad Mansourian said he and the transit agency will wait until receiving the results from the registrars in both counties before providing comment or advising its board of directors.

SMART’s board awarded a $103 million design-build contract for its first phase of construction early this month to railroad specialists Stacy and Witbeck Inc. and and Herzog Contracting Corp. The work will entail many underlying elements of the system, including tracks, railroad crossings and bridges.

Yet that 38.5-mile segment is shorter than the Cloverdale-to-Larkspur system proposed when voters in Marin and Sonoma Counties approved measure Q with a 70-percent majority in 2008.

RepealSMART argues that the shorter “initial operating segment” between Santa Rosa in Sonoma County and San Rafael in Marin County would not have engendered the same support for the tax, and residents should be given the chance to repeal the measure.

Revenue from a $191 million bond sale in December has been held in escrow pending the result of the repeal efforts. If RepealSMART fails, that funding will be released and used to finance three more contracts involved in the construction of the initial operating segment.