BART, a mass transit system that for years has ferried commuters to stylish tech companies in downtown San Francisco, may finally bring its own technology into the modern era.

Top agency brass are considering a potentially life-changing innovation for BART trains and stations: seamless Wi-Fi. Passengers have pleaded for a dependable network since the invention of smartphones, frustrated by calls that drop in the Transbay Tube, and web pages that stubbornly refuse to load.

The board is set to vote Thursday on a project that would add Wi-Fi and Bluetooth infrastructure, improving the cellular network and providing a wireless internet connection at all stations and on board its new Fleet of the Future trains. Construction would start immediately, but don’t expect instant gratification — it may take five years to finish.

The four-phase project could enable mobile ticketing and personal on-demand service alerts, while producing revenue for BART as it licenses fiber-optic cables along its rail lines. Contractor Mobilitie would cover all the costs of overhead, with BART not contributing a penny.

It’s part of General Manager Bob Powers’ effort to bring 21st century technology to a railway that crisscrosses the tech center of the world. Officials tried to do parts of this plan in the past, but a previous contractor didn’t deliver the desired service, and then sued when BART tried to pull out, stalling the effort for several years.

“We were in this area where we couldn’t move forward,” said board Director Robert Raburn, who touted the new project as “a win in so many ways.” It doesn’t just help passengers, he noted, it’s also good for agency managers, police and maintenance workers. With a sophisticated digital network, BART could check broken equipment remotely. If a crime happened on a train, police could immediately access surveillance footage.

“Our equipment would be able to talk to us whenever it needs help,” said Ravi Misra, assistant general manager of technology at BART. “That means our response will be faster, which translates into better (transit) service.”

Though BART is late to the game, it’s among several mass transit tech Neanderthals in the Bay Area. Muni commuters still pine for Wi-Fi, though it’s possible to piggyback on San Francisco’s public wireless network in some stations, according to spokeswoman Erica Kato. Caltrain will get Wi-Fi in 2022, when the Peninsula commuter rail goes fully electric.

In the North Bay, SMART trains and Golden Gate Transit buses offer wireless internet to passengers. Officials have not been able to replicate the perk on ferries, owing to tech issues on the water. AC Transit transbay buses and SamTrans’ commuter express shuttles to the Peninsula provide Wi-Fi service, though most city buses do not.

The BART contract, if approved, involves several steps.

First, BART would collaborate with Muni to add cell service in three San Francisco subway tunnels — Sunset, Twin Peaks and the forthcoming Central Subway. Then, BART would add wireless internet and Bluetooth beacons to its stations, making it easier to conduct a business meeting on the platform, or use a BART navigation app to find the restroom.

The third step: installing wireless transmitters to broadcast a secure signal to the new train cars, with small poles along the tracks to fill any dead zones. That would empower riders to watch a movie or browse email in the tunnel, or to quickly notify police during an emergency.

Last: new fiber-optic cable along BART and Muni rights-of-way, which could be licensed to make money for the transit agencies. BART estimates it will generate $243 million for the agency over 20 years from licensing the cellular network, the poles and the fiber.

Officials first dangled the possibility of system-wide Wi-Fi in 2009, when the transit agency signed an exclusive 20-year contract with Sacramento’s WiFi Rail. But the service was abysmal, and BART ultimately fought and won a court battle to extricate itself.

Passengers bustling through the concourse at Powell Street Station cheered the plan on Tuesday afternoon.

“Anyone traveling longer than 30 minutes will want to pull out their laptop and do some work,” said Priyanka Chaturvedi of San Francisco.

Victoria Ellis, an Australian tourist who is backpacking across the U.S., said she relies on functioning Wi-Fi to find her whereabouts after stepping off an airplane and onto the local mass transit system.

“It’s really critical to have a map application,” Ellis said, puzzling over the ticket machine at Powell. It was her first time using BART.

Ryan Husk of San Francisco was also excited by the prospect of reliable Wi-Fi and cell service — though he confessed that his BART commute is the only time he gets to unplug.

Director Janice Li, the youngest member of the board, expressed enthusiasm through what seemed like the most appropriate medium on Tuesday: by tweeting.

“As a Millennial I am unfunctioning without Internet,” she wrote. “I am excited to vote on this to enable myself to meme and ride transit at the same time.”

Rachel Swan is a San Francisco Chronicle staff writer. Email: rswan@sfchronicle.com Twitter: @rachelswan