"You're safer underground than you are above ground," said Richard Maloney, SEPTA spokesman. "We are not experiencing a crime wave."

Crime statistics, however, show that serious crime on SEPTA property has been on the rise for four consecutive years, with an 81 percent increase in serious crimes from 2004 to 2007.

Those figures came as no surprise to commuters, who said yesterday that they were worried and exercising more caution. One woman said she would start driving, while others won't wear jewelry and some said they were considering weapons for self-defense.

"Absolutely I'm concerned," said massage therapist Regina Stine, 24, who takes the train every day. "It does make me think about obtaining some form of protection, but I'm afraid that if I did that, someone would use my own weapon on me."

Police have also responded with more officers patrolling transit property and a higher concentration of police after school, when the number of teenagers in the system dramatically increases.

The fear follows the March 26 afternoon beating of Sean Patrick Conroy, 36, a Starbucks manager in Center City. He was beaten and kicked on the concourse at 13th and Market Streets.

A gang of teens later confessed to police that they were just fooling around and had no intent to kill Conroy, who suffered a fatal asthma attack triggered by the beatings.

Wednesday night, a 23-year-old woman was thrown to the ground walking through the Gallery underground. She lost a tooth and was surrounded by up to 12 people who kicked and punched her, and stole her purse.

Two juveniles and three adults, ages 16 to 20, were arrested after trying to flee on the subway.

Shirley Tilson, 51, said yesterday on her way underground at Eighth and Market that "I think I'm going back to driving in and parking."

Her companion, Dale Hayes, 54, shared her concern: "I'm down here every day. I just don't wear jewelry or carry electronic devices."

Maloney said the perception of wild teens' roaming underground and beating innocent victims was not accurate. In both recent cases, he noted, SEPTA police were on hand immediately and apprehended suspects.

"The question people are asking is, 'Is it safe for me and my family to ride the subway?' " Maloney said. "And the answer to that is, absolutely yes."

Maloney said he could not explain why crime in the SEPTA system was up.

So far this year, the number of crimes reported by SEPTA was higher than in the same period last year. The increase comes while violent crime across the city is declining.

Maloney cautioned that the number of crimes reported for the entire transit system, which handles an average of 314,000 people a day moving through more than 100 miles, is a fraction of the number of crimes reported citywide.

In 2007, there were 81,767 violent offenses reported in the city, a 12 percent decrease from 2006. SEPTA, meanwhile, reported 197 crimes compared with 109 in 2004, the lowest number in 19 years. In 1989, transit crime peaked with 1,463 serious crimes reported.

From 2004 to 2007, SEPTA reported that robbery went up 62 percent and theft went up up 113 percent. Aggravated assault dropped, with seven assaults reported in 2004 compared with four last year.

Homicides are rare. Statistics show no more than two in any given year - and in most years there are none.

Maloney characterized the fatal attack on Conroy as "a horrific aberration, a deliberate aberration that robbed a wonderful man of his life."