This was all part of a test so the transit agency could figure out what's behind a mysterious power surge that's been damaging trains.
RELATED: #DearBart: Riders sound off on crowded trains
Despite the problems and delays, BART officials say ridership numbers have not been significantly impacted. With so many thousands of people relying on BART daily, those officials and city leaders say a bond measure is needed to fix the aging infrastructure. Still, they don't know if the old system is what's causing this new problem.
BART service remains closed between North Concord and Pittsburg-Bay Point, but on Friday officials had one test car running the span with an expert from the East Coast onboard.
BART officials say that expert is armed with special voltage measuring tools.
"If we can at least identify the exact moment we're having the spike in voltage, it'll get us closer to cracking the code of what's causing this," said BART spokesperson Alicia Trost.
BART can't fix the problem until it identifies what's causing the problem. That's why the bus bridge will remain in effect through Monday.
RELATED: BART addresses questions about delays on social media
The problem has put a spotlight on BART's aging infrastructure.
"BART is in absolute crisis right now," said San Francisco Supervisor Scott Wiener.
The same system has been in place 45 years
"We have not kept up in terms of modernizing the system, addressing its infrastructure needs, and the system is unraveling," said Wiener.
District #3 BART Director Rebecca Saltzman added, "I've seen track stamped 1968, so we really need to get out and repair and replace it."
BART's directors and local supervisors say a $3.5 billion infrastructure bond needs to pass in November. Even if it does, individual counties would still need to pony up money to replace the aging cars.
RELATED: BART unsure when service will resume between 2 stations
BART says the now damaged cars could take months to fix.
To expedite the process, BART is taking working thyristors from eight train cars, it's a move that will fix 30 to 40 train cars over the next couple of weeks.
All the delays are really starting to wear down BART passengers. Riders were more than eager today to share their frustration with ABC7 News.
"On a good day, my commute is about an hour and a half. But on a day like today it's like two hours," said BART rider Steven Anyanwu.
Fellow BART rider Kathleen Corey added, "It's the worst part of your day because you just don't know what's going to happen. It's usually every morning and every evening you have a problem."
Besides the track problem, BART also experienced delays Friday morning through the tube and also around the Daly City station due an incident that involved police.
RELATED: BART officials explain what's causing delays, damage
We've done some math to help you understand just how big a problem all this is for BART. Fifty-eight cars have been damaged on the Pittsburg-Bay Point line. Add that to the other 80 damaged by a similar issue in the Transbay Tube.
That's 138 cars damaged in total, which means there's only 669 cars in BART's entire fleet. So that's more than 20 percent, or 1 in every 5 cars out of service, with these two incidents alone.
All of this centers around an electricity problem that essentially kills power to the cars. Engineers are working around the clock to try and find a fix.
They've pinpointed a single interlocking track between the two stations. Power surges have damaged a small, important, and expensive part called a thyristor. When it fails, the cars stop powering themselves.
BART mechanics tell us it will take five months for the replacement parts to arrive. BART says the tracks will be closed through Monday, at least.
"We've told the transit agencies that are helping with the buses to expect through Tuesday even," Trost said.
Uber is pitching in too. The ride-share company is expanding its car pool option, Uberpool, into the affected areas of the East Bay until BART gets back on track.
"One of the questions we asked is how do we provide lower cost options so people can more easily get from home to bart stations to work," said Wayne Ting, Bay Area general manager of Uber.
BART will be fixing damaged train cars over the next couple of weeks while waiting on a necessary part that can take months to order.
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.
For more stories about BART, click here.
The one test train car will be running at 70 mph equipped with special measuring tools— Melanie Woodrow (@MelanieWoodrow) March 18, 2016
Also happening today: BART taking thyristors from 8 cars that will ultimately fix 30-40 cars over the next couple of weeks— Melanie Woodrow (@MelanieWoodrow) March 18, 2016
Expert has special voltage measuring tool— Melanie Woodrow (@MelanieWoodrow) March 18, 2016
Happening today: BART is running a test train from N Concord to Pittsburg/Bay Point w/expert on board to ID what is causing voltage spike— Melanie Woodrow (@MelanieWoodrow) March 18, 2016
Spokesperson continues "However spotlighting our needs is always a good thing for the public to understand."— Melanie Woodrow (@MelanieWoodrow) March 18, 2016
Another BART spokesperson says: "we do not..know..cause of..spike in voltage so..can not say if.. from aging infrastructure."— Melanie Woodrow (@MelanieWoodrow) March 18, 2016
Right Now: Long line of people getting on bus headed to Concord/Martinez Bart station pic.twitter.com/KnRXPA36Ye— Janet O (@JanetONews) March 18, 2016
Bus arrives from Pittsburg station. Bart riders said it's adding at least 10 min to their commute pic.twitter.com/kpw118LBf5— Janet O (@JanetONews) March 18, 2016