OAKLAND (CBS SF) – Bay Area Rapid Transit platforms were crowded Friday morning with frustrated passengers as the massive transit system limped through a morning commute hampered by electrical problems in the East Bay and in the Transbay Tube.

The latest major service disruption began 8:48 a.m. when an electrical issue was reported in the Transbay tube with delays lengthening to 20 minutes.

What followed was an even more alarming tweet from BART officials.

System wide delays now up to 20 min due to existing power issues, trains running at reduced speed in areas, and multiple police holds. — SFBART (@SFBART) March 18, 2016

There was no immediate word on what had triggered the police holds at stations.

Transit officials had already warned BART riders that they could be looking at months of shorter, more crowded trains as a consequence of an ongoing electrical issue that afflicted part of the Pittsburg/Bay Point line Wednesday morning.

BART’s fleet is down 58 train cars from what it typically has after cars were hit with a damaging voltage spike while passing between the Pittsburg/Bay Point and North Concord/Martinez stations, BART Chief Mechanical Officer Dave Hardt said during a press conference Thursday.

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Although the precise reason for the electrical surge and the exact location of it is still being investigated, Hardt said the agency’s engineers have identified the damage it has caused to the cars’ propulsion systems – and the repair process could be lengthy.

“It’s going to take months for the fleet to be recovered fully,” Hardt said. He also said in his around 9 years with BART, he’s never seen an issue of this sort and of this magnitude.

BART officials first reported problems between the two stations shortly after 10 a.m. Wednesday. Train service between the stations has been halted since then and buses have been transporting riders.

Hardt said there’s a voltage problem that either stems from an oversupply of electricity or an issue the train cars are having with returning the power received.

He said the cause of the problem hasn’t been isolated. Potential reasons run the gamut from malfunctioning aged infrastructure to too much power coming from PG&E.

BART is flying in at least one outside expert in power control and protection and is consulting with PG&E officials to further investigate the issue.

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Hardt said that although the areas are not associated with the same electrical infrastructure, BART train cars were damaged similarly due to a problem mid-February in Oakland.

There were also intermittent train car propulsion failures around the same time in the Transbay Tube, which runs under the Bay and connects the East Bay with San Francisco.

The latest glitch, between Pittsburg/Bay Point and North Concord/Martinez, has not been intermittent. Hardt said there’s a silver lining in that, given that the source of this new issue can be isolated.

Hardt was not able to provide an estimate on when the cause could be pinpointed or how long the section of the track affected will go without train service, a separate timeline from when the BART fleet will return to its normal operation.

Earlier, BART spokeswoman Alicia Trost said there are typically around 590 train cars running in BART’s fleet during a weekday morning commute but only 534 were operating Thursday.

BART officials also said there were 11 trains shorter than usual by one car and five trains shorter by two cars Thursday morning.

Trost said riders should expect trains to be more crowded under such conditions.

Some of the train cars that need maintenance will require much more time than others to be re-introduced into the fleet to ease that crowding.

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Hardt said on the train cars that use direct-current components, the voltage spike impaired a device called a thyristor, which costs $1,000 each and are received sporadically from a specialized manufacturer.

BART’s engineers only had 12 on hand and may need around 100, Hardt said. Although some of the devices may be salvaged, buying these devices alone may cost up to an estimated $100,000.

The alternating-current model train cars, which have been updated much more recently, mostly sustained blown fuses – a much easier and less expensive fix, Hardt said.

Despite the damage the voltage spike caused to train cars, it did not present a danger to riders, BART officials said.

Buses will continue transporting people between the Pittsburg/Bay Point and North Concord/Martinez stations Friday, a trip estimated to take around 15 minutes.

BART officials apologized for the inconvenience and said crews were “working around the clock to identify the problem and fix it.”

BART train departure information can be found at bart.gov.

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