It’s been more than three months since those mysterious power surges knocked dozens of BART rail cars out of service — and while the transit agency has yet to pinpoint the problem, the costs keep rolling up.

To more than $2 million, in fact. And counting.

For starters, BART has spent more than $200,000 on outside consultants to search for the electronic gremlin that nearly brought the system to its knees. The problem started with the electrical components on a handful of cars blowing out near the West Oakland Station on Feb. 20. Over the next three weeks, a total of 80 cars were knocked out of service.

The problem popped up next between North Concord and Pittsburg-Bay Point, knocking another 50 cars out of service and forcing BART to run a bus bridge for days between the stations.

Then, as mysteriously as it had appeared, the problem vanished.

“The issue has completely gone away, and we have fully recovered from it in terms of our our car count,” said BART spokeswoman Alicia Trost. “But we still need to find out what caused it so it doesn’t happen again.”

And with good reason. BART documents we obtained through the state Public Records Act show that, in addition to the consultants, the agency has spent $800,693 on labor, $332,449 on parts and $771,703 on test equipment related to the electrical glitches.

BART also spent $134,472 on that bus bridge. And, it lost $265,000 in fare revenue between Pittsburg-Bay Point and North Concord.

Total cost to date: $2.5 million.

But wait, there’s more.

As part of that $200,000 in consultant costs, BART has hired experts to do a computer analysis of all the electronic data collected from the cars and elsewhere to “see if they find patterns we don’t see,” Trost said.

“There could be more costs if the data team comes back wanting more testing,” Trost said.

More money: The Democratic duel for U.S. Senate between state Attorney General Kamala Harris and Orange County Rep. Loretta Sanchez has put a number of big donors in a box. After all, no matter who wins, Democrats are going to get a Senate vote out of the deal.

Harris raised $10.2 million during the primary, nearly three times as much as Sanchez, but has only about $2.5 million left in the bank.

That looks good compared with Sanchez, however. She’s down to her last $500,000.

Sean Clegg, a consultant with the Harris operation, said the campaign expects to raise millions of dollars more for the fall showdown. He’s counting on a boost from a USC Dornsife/Los Angeles Times poll that found Harris leading Sanchez out of the gate, 47 percent to 22 percent.

“She has built a national network, and is the No. 1 fundraiser in an open seat” among Senate candidates, Clegg said.

Bill Carrick, who is running Sanchez’s campaign, acknowledges that he has his work cut out. He hopes to raise $6 million to $7 million for a race that he figures is wide open, given the much larger turnout expected in November.

“It will be a very different electorate — younger and more diverse, from all over the state,” he said. “I think the opportunity favors Loretta.”

Even before Harris’ primary victory this month, Democratic Rep. Jackie Speier of Hillsborough was fielding questions from House colleagues about which candidate to put their money on in the general election.

“They all want to be on the right side of the winner,” said Speier, who has yet to endorse in the race.

The final tab: We now know the tab to taxpayers for those San Francisco City Hall protests staged by supporters of the Frisco Five hunger strikers, which helped set the stage for Police Chief Greg Suhr’s exit.

An audit by the city controller puts the cost at $361,000, most of it for the Sheriff’s Department.

Deputies confronted protesters when they stormed City Hall on May 6 and demanded to meet with Mayor Ed Lee. Activists smashed some of the building’s front windows and destroyed at least one metal detector during the protest, which lasted eight hours and ended in 33 arrests.

More protests followed over the next two weeks. The total tab to the city included $88,669 in deputies’ pay and nearly 3,000 hours of overtime totaling $252,514.

Taxpayers are also on the hook for $10,000 to replace the trashed metal detector, plus thousands more to replace broken widows and repaint walls damaged by protesters.

Given the chaotic scene, most of the protesters were cited only for trespassing and aren’t likely to be prosecuted, said spokesman Alex Bastian of the district attorney’s office. But he said the Sheriff’s Department is still investigating to see if anyone can be linked to the vandalism, in which case they could be charged.

San Francisco Chronicle columnists Phillip Matier and Andrew Ross appear Sundays, Mondays and Wednesdays. Matier can be seen on the KPIX TV morning and evening news. He can also be heard on KCBS radio Monday through Friday at 7:50 a.m. and 5:50 p.m. Got a tip? Call (415) 777-8815, or email matierandross@sfchronicle.com. Twitter: matierandross