Is it a bus or is it a trolley? New SF Muni fleet can go...

Regular riders of Muni’s trolley bus lines are starting to notice the changes. Low floors. Navy blue seats instead of brown. Motors that thrum as quietly as a dishwasher on a light rinse cycle.

The aesthetic differences are subtle, but the new fleet provides other, more important benefits that commuters can’t see.

Muni’s 185 new 40-foot electric trolleys are gliding all over the city. They roll along the 1-California route, from the Financial District up through Russian Hill and into the Richmond. They’re visible on routes such as the 22-Fillmore, the 24-Divisadero and the 31-Balboa. They resemble Fisher-Price toys: gray with thick red stripes and trolley poles dangling from the roof.

“To me, they’re better buses,” said Kam Wong, who was waiting for the 1-California at Sacramento and Montgomery streets Friday, holding a small Chihuahua on a leash.

Made by New Flyer, the new buses have powerful batteries that enable them to go off the overhead wires for several miles at a time. That allows the San Francisco Municipal Transportation Agency to provide continuous service if a fire flares up, forcing the bus to take a detour. It also ensures the buses keep running when work crews have to shut off the wires for construction projects — a frequent occurrence, with the SFMTA’s new “quick-build” policy to redesign streets throughout the city.

The new buses are more reliable, said Director of Transit Julie Kirschbaum. Besides having stronger batteries and being more impervious to disruptions, they simply won’t break down as often as their predecessors. The older trolleys, made by long-defunct Electric Transit Inc., accounted for only 20% of Muni’s bus fleet but 40% of its breakdowns.

“This is the last piece of a really comprehensive program to improve our vehicle fleet,” Kirschbaum said. She’s taken a methodical approach to the problems that dogged San Francisco’s transit system for years, from mechanical glitches to operator shortages to bottlenecks at certain intersections.

Seven years ago, San Francisco had the oldest, clunkiest buses and trains in the nation. Then-transportation chief Ed Reiskin began overhauling the agency’s vehicle stock in 2012, replacing old diesel buses with hybrids and swapping the heavy rail cars of yore with a sleeker, easier-to-maintain model. In 2017, Muni announced plans to update its trolleys.

While the railcar rollout has stumbled, the 800 new buses have fewer delays and meltdowns, Kirschbaum said.

“That’s a fabulous thing for longtime riders,” said Cat Carter, interim executive director of San Francisco Transit Riders, a grassroots advocacy group that presses for better bus and train service.

Carter moved to San Francisco in 1999, two years before the previous generation of trolleys hit streets. She recalls many bus rides in which the pole would suddenly detach from the overhead wire, requiring the operator to “get out, play with it for a while and finally get the wire reattached.” Throughout that process, the bus might be marooned in an intersection, forcing cars and pedestrians to awkwardly maneuver around it.

Such problems should be a thing of the past, Kirschbaum said. Many of the old buses are sitting in Muni’s Presidio yard on Geary Boulevard, where workers strip out equipment that can be salvaged, such as fare boxes. Most of the vehicles will be auctioned in Sacramento and then scrapped for wire and metal. Some might get a second life as Burning Man art cars.

At least a few San Francisco residents will mourn the old brown seats.

“The new ones aren’t as wide,” said Antonio Jones, who was catching the 1-California on Friday from the Financial District to his home near Alamo Square.

Like everyone else, Jones appreciates the extra battery juice. “I just don’t like the interior,” he said.

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