LAFAYETTE (KPIX) – No way around it, this weekend’s BART shut down in Contra Costa County will deliver plenty of delays and inconvenience. But if you’ve ever felt inconvenienced by BART, this is what solutions are going to look like — not just minor improvements, but entire rebuilding.

“It’s a major rebuild,” says BART spokesman Chris Filippi. “We’re talking 5,000 feet of rail, 10,000 feet of train control cabling.”

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Antioch to Millbrae is the busiest BART line, but on the weekend of August 17 and August 18, there will be no trains between Orinda and Walnut Creek. That is when crews will begin replacing track that is nearly 50 years old, and nearly three million pounds of rock ballast beneath it.

This is the first of six such weekend closures of the BART line and it’s a job so big it will require the use of Highway 24.

“It’s a very limited workspace, and because of that we have to close, temporarily, two of the eastbound lanes during track shut downs,” Filippi explains.

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That narrow track space speaks to one of BART’s notorious flaws. The track in Lafayette is really no different than the Transbay Tube; two parallel tracks that don’t allow much wiggle room when something goes wrong. The rebuild in Lafayette will include a pocket track, where a disabled train can be tucked out of the way.

“What we’re trying to do is basically backfill and create that flexibility for the system,” Filippi says. “That’s going to make us more reliable, and allow us to work through problems in the future much more quickly.”

BART has suffered from a lack of upkeep in decades past, and that is what has caused many of the problems riders now know well. This scale of upgrade work is what making up that underinvestment in the basics looks like: major projects that come with significant inconvenience, but should provide better service long term.

“And you’re going to see more and more of this as we move into the future,” Filippi says. “Thanks to voters approving Measure RR back in 2016, we have $3.5 billion to fund this sort of critical infrastructure work that we really need to get to work on.”

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Caltrans will be monitoring traffic during the weekend work. If eastbound delays climb to 30 minutes, BART will re-open one of the lanes to mitigate the delay.