The marriage is almost over.

After the money disputes, the public spats and numerous lawsuit threats, SamTrans and BART are calling quits to the 17-year partnership behind the underperforming BART-to-SFO extension.

Not to worry: The BART line — which connects Colma, South San Francisco, San Bruno, Millbrae and San Francisco International Airport to the rest of the Bay Area — will survive, but the relationship between SamTrans and BART is about to end in divorce.

For some six months, the Metropolitan Transportation Commission, the Bay Area's regional transportation governing body, has tried to draw the feuding agencies toward an amicable conclusion of their partnership.

On Wednesday morning, before the MTC's Planning and Allocations committee, the commission came one step closer to success — and with any luck, said transportation officials, the MTC and BART boards will approve the agreement by the end of the month.

"In the spirit of Valentine's Day, I hope we can all move forward," SamTrans director Mike Scanlon told the committee Wednesday morning.

What went wrong?

Money, of course.

Under the terms of the marriage, SamTrans agreed to accept the operating costs of the Peninsula's five-stop BART extension. That shouldn't have been a problem: The new BART line was supposed to be one of the first transit operations in the country to achieve more than 100 percent fare-box revenue, essentially paying for itself through fares. For SamTrans, the idea was to kick back and watch the money roll in.

Only, 9/11 and the subsequent dot-com bust ended that dream. Initial daily ridership projections were pegged at 50,000. But since the line's SFO extension arrived in 2003, it has only drawn some 30,000 riders a day. Although both BART and SamTrans herald the line's 70 percent fare-box recovery as an unprecedented success for Bay Area transit, operating the extension still costs SamTrans the remaining 30 percent.

"The extension was never supposed to cost SamTrans a penny," said SamTrans spokesman Jonah Weinberg. "Unfortunately, it has never met the expectation that it would be wildly successful."

Not being "wildly successful" has cost SamTrans as much as $17 million a year to run the line. Since 2003 the borderline debacle has cost the agency

$48 million. The marriage with BART quickly soured when the two agencies started to bicker about the amount of money which the underresourced SamTrans had to pay annually toward operating the extension.

Last year SamTrans even capped the amount of money paid to BART at $5 million. Shortly thereafter the MTC stepped in to broker an end to the marriage.

"We were certainly on a bad course," said Scanlon. "This (agreement) is reasonable — and as good of a solution we could have come to in order to deal with an extremely complex problem."

Under the terms of the divorce proceedings, SamTrans washes its hands of the extension by allowing BART to take full control of its rail line. In return for the trouble, BART would receive $32 million — the lion's share of SamTrans' anticipated portion of bond money from the voter-approved Proposition 1B. Alongside an additional $800,000 from SamTrans' annual share of state transit funding toward BART, the funds will go toward the construction of a BART extension to Warm Springs in Alameda County, a project that SamTrans was supposed to have helped fund with revenue from the money-losing extension.

In addition, the San Mateo County Transportation Authority would continue to pay BART 2 percent, about $1.2 million a year, of the county's half-cent sales tax toward the Warm Springs extension.

"No divorce is a good thing, but given the situation, this is the best solution for everyone involved," Weinberg said.

While SamTrans has suffered through this difficult marriage, so have county taxpayers and commuters. In a desperate attempt to cut some of the costs, SamTrans has spent the last few years consolidating BART train lines and reducing service — cutting out direct trains to Millbrae and increasing wait times at the airport from seven to 15 minutes.

Both BART and SamTrans officials insist that handing the operating of the extension over to BART will only benefit riders. 

"Instead of being constrained by the building limitations that SamTrans imposed," said BART spokesman Linton Johnson, "we'll be able to run the service that the customers want." As BART conducts ridership surveys and budget studies on the extension, service changes could arrive as early as the fall, Johnson added.

The divorce, said Johnson, is the unfortunate result of two parents who have "opposing viewpoints and opposing budget limitations" on how to raise a child.

"We wanted the kid to grow up really fast and be a genius at a young age, and (SamTrans) wanted the kids to grow up really fast, too, but they weren't willing to pay for it," he said.

Only, Weinberg said, SamTrans has a "bunch of children to look out for " — citing the agency's bus fleet and paratransit, plus Caltrain, which the agency jointly funds alongside agencies in Santa Clara County and San Francisco — and "couldn't benefit any one of our children to the detriment of the others."

In the meantime, Weinberg said, "we wish our child to grow and prosper now that it's left home."

Staff writer Michael Manekin covers transportation. He can be reached at (650) 348-4331 or by e-mail at mmanekin@sanmateocountytimes.com.