Since starting service in August, the North Bay’s new commuter rail service has survived a fire that stopped at its tracks, given thousands of free rides to help fire victims and has had to fight to collect promised federal funding for a new extension to Larkspur.

In short, SMART has been on something of a wild ride in its nearly six months of hauling passengers between Santa Rosa and San Rafael.

Yet the service has still managed to meet or exceed ridership and revenue projections, and start work on that Larkspur extension, which will bring the train’s riders to within a short walk to the Golden Gate Ferry to San Francisco.

But Sonoma-Marin Area Rail Transit’s biggest achievement may be that the passenger rail service, the first in the North Bay in 60 years, seems to have won over skeptics and critics, who are now calling for more service and more stations.

“It’s only been six months,” said Randy Rentschler, a spokesman for the Metropolitan Transportation Commission, “but I think this shows that there’s a need for more than just a highway in that corridor. SMART has the opportunity to be a really great alternative.”

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Aboard the gray and green trains Thursday, commuters, sightseers and day-trippers raved about the service, especially the opportunity it provides to avoid Highway 101’s torturous traffic.

“I love it,” said Jennifer Romo Dowd, 40, a meeting planner who lives in Sebastapol and since October has commuted on the train between Cotati and downtown San Rafael. “They’re on time, they’re comfortable, there’s beer and wine, and the Wi-Fi works most of the time. It’s a great alternative to driving.”

SMART’s trains make 17 round trips between San Rafael and Santa Rosa on weekdays and five each way on weekends and holidays. The trains are diesel-fueled and self-powered, meaning they aren’t pulled by locomotives.

Most consist of two cars, one with a restroom, the other with a cafe that serves snacks and beverages, including locally produced beers and wines. But higher-than-anticipated ridership on some trains, including a larger-than-expected number of passengers who bring bicycles aboard, prompted SMART to add a third car to 14 weekday trains, most of which run during the morning and evening commutes.

SMART has carried more than 310,000 passengers since its start, said Jeanne Mariani-Belding, an agency spokeswoman. That’s slightly ahead of projections, despite the steep drop in the days after the North Bay fires and fluctuations that vary with the weather. When it rains, fewer bike riders commute, and when it’s warm and sunny, day-trippers and sightseers show up in larger numbers.

“It has not been a typical six months,” Mariani-Belding said. “We had wildfires, we had limited service, we had free rides, we had the holidays. Our ridership fluctuates, and it’s going to take a while to level out.”

SMART is also running ahead of revenue projections, meaning passengers are taking longer rides that expected. SMART had predicted it would collect $68,000 in fares each week but is averaging about $76,000 even with the free rides.

The busiest stations are Petaluma, downtown Santa Rosa, downtown San Rafael and Sonoma County Airport. The most popular destinations are downtown San Rafael, downtown Santa Rosa, Marin Civic Center and Petaluma.

Thursday’s passengers, many of them occasional or first-time riders, said they were eager to see more trains, extended hours and the opening of promised extensions south to Larkspur and north to Windsor, Healdsburg and Cloverdale.

“I’m not a commuter; I do this for fun,” said Sally Mayer, 61, of Novato, who rides SMART to meet friends for lunch. “We’d really like to take it to downtown Santa Rosa for dinner. We have some favorite places there. But the last train back leaves at 7 p.m.”

The 2.2-mile Larkspur extension, considered crucial to attracting San Francisco-bound commuters, started last summer but faces funding challenges, including uncertainty over $22.5 million in federal money promised in 2016 but delayed by the Trump administration.

Farhad Mansourian, SMART’s general manager, said he recently met with Jane Williams, head of the Federal Transit Administration, in San Francisco and is optimistic the funds are coming soon. Bay Area transportation officials feared a repeat of the spring 2017 fight Caltrain had to wage to get promised federal money for electrification.

“Things are taking a little bit longer than usual,” Mansourian said Friday, “but as of today, our target date is early March.”

SMART expects to run trains to Larkspur by the end of 2019.

Extensions northward will take longer. SMART plans to make it to Cloverdale, but the next anticipated stop 3 miles north of the current end-of-the-line Sonoma County Airport Station in Windsor lacks funding, although the plans have been drawn up and the environmental studies are completed. Even so, Mariani-Belding said the extension could be completed as soon as 2021.

State transportation officials are also interested in seeing SMART eventually run east along Highway 37 using existing rails to Fairfield. The agency has applied for a grant to study the feasibility.

SMART’s biggest challenge, exacerbated by the Tubbs Fire, which stopped right at its tracks near the Santa Rosa North Station, is hiring and retaining train operators and conductors scared off by the Bay Area’s high price of housing. The SMART board recently approved hiring more people to run the trains, but it can be tough to pay them enough.

“As soon as we’re able to hire new people,” Mansourian said, “we’d like to add more service, including earlier service on weekends and filling some of the gaps in our schedule.”

While SMART is off to a promising start, he said much work remains.

“It’s a fantastic beginning,” Mansourian said, “but look at it this way: We’re like a startup. We’re not done.”

Michael Cabanatuan is a San Francisco Chronicle staff writer. Email: mcabanatuan@sfchronicle.com Twitter: @ctuan