Crime was up on BART by more than 20 percent this year — most of it involving the theft of cell phones and other electronic devices — even before a group of youths swarmed a train Saturday, according to the transit system’s interim police chief.

The increase of approximately 22 percent from the same time last year comes despite a drop so far in 2017 in car break-ins, as well as automobile and bicycle thefts, said interim Chief of Police Jeffrey Jennings. It also reverses three years of declining crime rates.

The spike had stirred extra police patrols at some stations before at least 40 juveniles and young adults rushed aboard multiple cars of a Dublin-bound train at the Coliseum station and robbed passengers Saturday night. Since March 11, there have been extra patrols, and 19 people aged 12 to 21 have been arrested on robbery charges, Jennings said.

“In the first quarter, we saw a significant increase in crime,” Jennings told BART’s board of directors Thursday at an unusual evening meeting. As for Saturday’s mass robbery, “we haven’t had anything of this scale before. There have been incidents with two to 12 people, but nothing this large.”

To deal with the current situation, BART has increased overtime spending to deploy more officers to stations hit by crime. Thursday, Jennings also shifted to emergency staffing levels; officers will work five days on with two days off, rather than four days on and three days off.

Saturday’s incident wasn’t on the meeting’s official agenda, but it was discussed as the first order of business.

There were questions about the timeline of the incident, which was first reported at 9:27 p.m. as multiple youths jumping the fare gates. By the time the first police car arrived at 9:32 p.m., they were gone. Several suspects have now been identified — in part because at least one of the cars that was stormed had a working video camera.

Mostly, though, directors emphasized their concern for the victims, as well as the station staff members who are powerless in such situations to do anything except call for help.

“I’m horrified at what happened this weekend,” director Lateefah Simon said after Jennings’ presentation. “What we want is for our riders to be comfortable and safe.”

Coincidentally, an item that was on the agenda involved the strategies by which BART staff hopes to cut down on the growing problem of fare evasion, which is estimated to cost the system somewhere between $15 and $25 million.

Some of the responses include what is called “station hardening,” such as taller fare gates and higher barriers between the free and ticketed areas of a station — changes made last winter at the Pittsburg/Bay Point station. Elevators that go from outside a station directly to the platform, such as at Powell Street in San Francisco or the North Berkeley station, would be relocated.

Another change would include giving police officers and new inspectors the ability to move through stations or cars and require passengers to show they have a valid ticket for their ride. This is done on Muni and is common on other urban transit systems.

Judging by the discussion after the presentation, BART directors are more comfortable with raising obstacles to hopping the gates than demanding proof of payment. One, Director John McPartland, raised the specter of fare evaders causing injuries to other patrons as they fled inspectors.

“I’m very much in favor of making our stations more secure,” McPartland said. “Put staff on plaforms going after fare evaders? As far as I’m concerned, not a chance.”

Others said fare evasion is a too-obvious symbol of recent problems in the system, from frequent delays in service to the common sight of people panhandling on cars.

“We’re getting to have a culture on BART where too many people decide that because of X or Y or Z, they don’t have to pay for a ticket,” said Director Deborah Allen. “We run trains, and people need to pay for their rides.”

There is no correlation between increases in fare jumping and the recent jump in crime levels, Jennings said. However, he suggested to reporters outside the meeting that the two topics are related.

“If we crack down on fare evasion, you will see a reduction in nefarious acts,” Jennings said. “People who come into the system with crime on their mind are probably not going to buy a ticket to get in.”

No vote has been scheduled on what steps to take to tamp down on fare evasion. Even if all the staff suggestions are implemented, nobody expects the problem to go away.

“The idea is not to catch people. The idea is to deter them,” said Paul Oversier, BART’s assistant general manager for operations. “If we wanted to get down to no fare evasion at all, we’d have to spend more than we saved.”

John King is a San Francisco Chronicle staff writer. Email: jking@sfchronicle.com Twitter: @johnkingsfchron