While aggravated assaults and larcenies rose, robberies dropped 32 percent, a decrease Sullivan said reflected the MBTA's push to prevent cellphone thefts through awareness campaigns and decoy operations. Cellphone robberies, which he said make up the majority of robberies, have dropped 44 percent this year compared with last, he said.

"We're not happy with an 11 percent increase," said Lieutenant Detective Richard Sullivan of the Transit Police. "Not to be cliché, but we really do strive for excellence here at the transit department. We're committed to bringing those numbers down."

Major crimes on the MBTA are up 11 percent this year by Oct. 1, compared with the same period last year, according to figures from the Transit Police, a hike officials attribute largely to an increase in aggravated assaults, as well as a sharp spike in bicycle thefts.


Overall this year, by Oct. 1, Transit Police have recorded 694 reported major crimes, which include homicide, rape or assault to rape, robbery, aggravated assault, burglary, larceny, auto theft, and arson. The same period last year saw 627 major crimes.

Sullivan said police are troubled and perplexed by a 31 percent rise in aggravated assaults, for which he said officials have not been able to determine a cause. By Oct. 1 this year, according to police statistics, 97 aggravated assaults had been reported, compared with 74 last year.

"There's no pattern that we can address," said Sullivan. "We have very talented crime analysts. We have looked at that. . . . If there was a pattern that was emerging or developing, we would go at it from that way, but we have not seen that."

He said that assaults often occur between "known combatants" who encounter each other on the MBTA, a situation that is difficult to prevent.

Two particularly brutal attacks occurred Tuesday.


At Malden Center Orange Line station, a 24-year-old Chelsea man allegedly struck an 18-year-old man in the head with an aluminum baseball bat at around 5:25 p.m., causing serious injuries. On Friday, said Sullivan, Transit Police obtained a warrant for the man's arrest on a charge of assault with intent to murder. He declined to give the suspect's name Friday because he had not yet been located. He also declined to say whether the alleged assailant and victim knew each other.

In an apparently unprovoked assault at Central Square MBTA station, Candace Daley, 32, allegedly attacked another woman with a screwdriver at about 7:30 a.m., cutting her face and kicking her before a bystander intervened, according to a police report. Cambridge police arrested Daley. Sullivan said Transit Police had been in the middle of a shift change when the call came in and requested that Cambridge police respond.

The biggest driver of the rising crime rate, however, was an increase in larceny. Larcenies make up nearly 70 percent of all reported crime on the MBTA and are up 23 percent this year compared with last year, according to police statistics. Most of the larcenies, Sullivan said, are of bicycles.

"It's the bikes this year," said Sullivan, who said bicycle theft has risen 50 percent compared with last year. "We're not happy, we're not pleased with it. We by no means are giving up on it."

Sullivan said many of the thefts are of bicycles parked in MBTA bike racks for days at a time. He said T officials are trying to raise awareness among riders about the importance of taking bicycles home at night. They have also increased uniformed patrols and have been running decoy operations.


Transit officers set up a decoy operation at Alewife, where several bikes were stolen in June. On the first day, he said, they made an arrest, and bike larcenies stopped at Alewife for several weeks.

No homicides have been reported this year, compared with one last year. Rape and assault to rape rose by two, from three attacks last year to five this year, according to statistics. Nine burglaries were reported this year compared with eight last year, and four cases of arson were reported this year compared with none last year. This year and last year, there were 10 reports of auto theft.

The MBTA logs more than 1.3 million rides every day, said Sullivan.

Paul Regan — executive director of the MBTA Advisory Board, which provides oversight to the T — said that in surveys he has conducted, riders say they feel safe. The raw numbers detailing the T's major crimes, he said, show that crimes of serious violence are relatively rare on the T.

"You're seeing the fruition of five to 10 years of spending on things like security cameras and a greater security presence," he said. "The obvious presence of cameras and security is reducing the incidence of a lot of these crimes."

And given the millions of riders that use the transit system, he said, a total of 694 reported major crimes is low.


"That is an astronomically small number of crimes, given the volume the T handles," he said. "You hate to see them trending up, in any circumstances. But I think that people believe the T is safe. I believe the T is safe."

Evan Allen can be reached at evan.allen@globe.com.