Even as traffic jams and crowded trains start to feel like distant memories, Caltrain officials are mounting a campaign for a new sales tax measure they say will allow the rail line to carry thousands more passengers up and down the Peninsula — once the world is no longer sheltered in place.

The measure would raise $108 million per year for the agency with a new sales tax of one-eighth of a cent in Santa Clara, San Mateo and San Francisco counties if voters approve it this fall.

Caltrain would put that money toward its ambitious plans to provide more frequent service with a new fleet of electrified trains. That would allow the agency to shift over the next several years from a commuter railroad whose schedule riders must plan their days around to one more comparable to BART, with service so frequent passengers just show up at a station and ride.

The campaign took a first step toward the November ballot on Wednesday, when the SamTrans board of directors gave its support to a potential measure. Six other government bodies — each county’s board of supervisors, plus VTA, the San Francisco Municipal Transportation Agency and Caltrain’s board — will also have to sign on before voters see it on their ballots this fall. The tax will need a two-thirds majority to pass.

“Providing Caltrain with a dedicated source of funding will finally allow the system to operate the fast, frequent, electrified service that our communities deserve,” Karyl Matsumoto, a South San Francisco city councilmember and chair of the SamTrans board, said in a statement.

Funding from the tax measure would help Caltrain run 168 trains each weekday between San Jose and San Francisco by 2022, officials say, with trains arriving every 10 minutes during peak commute hours. Gilroy and southern Santa Clara County would see more frequent service as well.

Looking further into the future, Caltrain has plans to eventually run over 200 trips per day and extend its tracks to downtown San Francisco’s Salesforce Transit Center.

Caltrain now typically has 92 trips each day, but last month slashed that service to 42 trains because of the coronavirus pandemic.

The measure would also provide a new revenue source for an agency that has seen ridership all but evaporate as millions of Bay Area residents stay home. Caltrain relies on passenger fares for 70 percent of its operating budget, with the rest coming from each of the three counties where it operates.

The agency will receive a share of the $1.3 billion in stimulus funding the federal government is providing to the Bay Area’s public transit systems, which should help soften the blow, though exactly how much money Caltrain will get hasn’t been determined.

Matsumoto said the pandemic is “a reminder that when we come out of this crisis, the (Caltrain) system will not be able to grow without dedicated investment.”

But there were signs of trouble for transit funding even before COVID-19 upended public life. Voters in Sonoma, Marin and Contra Costa counties rejected transportation sales tax measures like the one Caltrain is pursuing by wide margins on Super Tuesday. And with so much attention focused on the coronavirus, Faster Bay Area, the leading campaign for a Bay Area-wide sales tax increase this November that would have raised $100 billion for major transportation projects such as Caltrain’s, announced last month that it is postponing its campaign to a future election.

Caltrain’s proposal would impose a smaller tax than each of those other measures, though, and would fund a well-established rail line that has seen its ridership double over the past 15 years.

Another significant difference: While the regional “mega-measure” needs the state Legislature and governor to pass a bill authorizing it to appear on ballots across the Bay Area, Caltrain already has that green light thanks to legislation approved in 2017.

A January poll conducted by Silicon Valley Leadership Group — one of the leaders of the Faster Bay Area campaign and a backer of the Caltrain proposal — found 68 percent of respondents were in favor of a one-eighth sales tax to fund the railroad. Of course, January feels like a very long time ago, so the business group noted it’ll need to do more polling on the measure “when the global health and economic situation is more clear.”