BART to continue running limited service between North Concord and Pittsburg-Bay Point

CONCORD, Calif. (KGO) -- BART is restoring limited train service during commute hours between North Concord and Pittsburg/Bay Point.

On Tuesday morning, passengers will again be able to take trains between North Concord and Pittsburg, but only from 4 a.m. until 9 a.m. From 9 a.m. until 3 p.m., it's back to the bus bridge.

RELATED: BART officials explain what's causing delays, damage

The move comes after a weekend of extensive testing to try and figure out what is causing a surge that damaged more than 50 train cars last week.

During the peak of the commute, trains will run every 15 minutes with no bus bridge option. Bus bridges will begin running after peak commute hours are over, starting at 8 p.m.

BART officials said they prefer people taking BART over the bus bridge while they conduct testing, so they can use the weight of people on the trains, which seems to help them while running tests.

RELATED: #DearBart: Riders sound off on crowded trains

BART ran a six-car test train Monday with no problems, but when a three-car train was added into the mix, they ran into a problem.

"We got a little optimistic and we added another train to that loop, thinking, let's see how the system does if we add one more train to it and we had a propulsion problem," said BART spokesperson Alicia Trost.

Expert engineers armed with sophisticated measuring tools are close to pinpointing the voltage problem that has zapped dozens of BART train cars between North Concord and Pittsburg/Bay Point.

"What they saw in the measurements this weekend is a very short, we're talking micro seconds spikes in voltage," said Trost.

RELATED: BART addresses questions about delays on social media

For most of Monday, passengers had the option of taking the bus bridge at North Concord BART station or hopping on a test car. "I kind of just got on and they were like, 'it's going to Pittsburg,' it's better than getting on a shuttle," commuter T'keyah Brewer said.

"We are systematically laying out every possibility and then one by one eliminating them," Trost said.

While one team focuses on finding and fixing the electrical problems, another team is working to repair the damaged cars.

BART said it fixed 36 cars this weekend, but commuters said the buses are still crowded. "Some people are upset about it, but they should be really, really happy that BART is giving us the buses," commuter Sharon Kincaid said.

"They should have had a better handle on this," Victor Osborne said.

Whether you're understanding or not, it may take a while until BART isolates and fixes the problem. Until then, your rush hour commute will likely require some flexibility. "If they can't figure it out they may have to replace it. If they can't replace it then we have got to think of something new," Brewer said.

Tuesday's commute will bring more changes. Officials said only a train will run every 15 minute between the hours of 4 a.m. to 9 a.m. Then, from 9 a.m. to 3 p.m. only the buses will run.

You can also join the conversation by posting on social media with the hashtag #DearBART. We're looking for video messages or comments that you want shared. We might use them on air or online.

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