"We've got a drama coming down the street," said Whitfield, one of 16 school district police and security officers positioned around the Stenton Avenue high school last week at dismissal time.

Several school officers attempted to calm a verbal exchange between two students - a dispute over the affections of a cheerleader. One student was joined by his adult uncle.

As the argument intensified, three 14th District Philadelphia Police cruisers arrived, part of a contingent of city police patrolling the school's perimeter. The uncle, screaming obscenities, was ushered off school property.

Danger averted. A typical dismissal at a city school.

"At 3 o'clock, all hell breaks loose," said Capt. Winton Singletary, commander of the 14th Police District in Northwest Philadelphia. "Some days, we just race from school to school."

Every afternoon of the school year, 260,000 students are dismissed from Philadelphia's public and private schools. For officers from the city, SEPTA and the school district, dismissals pose a huge challenge - how to manage a tempestuous multitude equal to the combined populations of Allentown, Trenton and Wilmington.

The task is particularly difficult in neighborhoods with multiple schools, or at transit hubs, where crosscurrents of students from rival schools can collide and roil, and where gangs prey like piranha on the vulnerable.

Despite the heightened police presence - in the 14th District, it's all hands on deck during dismissal hour - altercations happen.

On Feb. 25, two Masterman High School students were attacked after school, sending one to the hospital. In January, about a dozen girls slashed two female classmates after dismissal at West Philadelphia High School.

Gangs of youths last month attacked students in the Broad Street subway in North Philadelphia, prompting Philadelphia police to dispatch a team underground to beef up SEPTA's patrols.

As alarming as this year's reports may seem, the number of after-school incidents is not remarkably different than last year's, when 815 crimes were reported to the district, said James B. Golden Jr., the Philadelphia School District's chief safety executive. Most incidents reported during the "extended school day" are assaults on students and robberies, he said.

Philadelphia is not alone.

In Camden, a unit of 17 officers is assigned to school patrol, and it concentrates on separating middle school pupils from more aggressive high schoolers, said Lt. Anthony Carmichael.

In Upper Darby, Police Superintendent Michael Chitwood Sr. says he focuses on 5,000 high schoolers who attend three neighboring Lansdowne Avenue high schools: Upper Darby, Archbishop Predergast, and Monsignor Bonner.

"A tremendous amount of police resources are deployed to make sure these kids get home safely," said Chitwood, who pays six officers overtime to come in early on school days to supplement his regular force.

In Reading, school officials two weeks ago neglected to inform police of the Dominican Republic independence day planned on Feb. 27. When Reading High School let out, a celebration turned into a riot as a thousand students overwhelmed the officers stationed near the school, disrupting traffic and vandalizing vehicles.

"There's no foolproof way to stop all of it," said Ron Stephens, executive director of the National School Safety Center, Westlake Village, Calif. "It's an ongoing challenge for schools everywhere."

In Philadelphia, school and police officials say they welcome efforts by parent groups to stand watch to provide safe corridors for homeward bound students.

The strength of a school's leadership is also critical. Community leaders cited a turnaround at Roxborough High as an example.

A year ago, marauding students so disrupted the Ridge Avenue business district that many merchants locked their doors at 3 p.m. and threatened to sue the school district, said Jack Wheeler, president of the Roxborough Business Association. He said youth behavior improved this year after a new principal, Richard J. Jenkins, took over.

"He's really changed the discipline," said Wheeler. "It's just amazing, the difference. Our business district - now we see a lot more people walking and shopping."

Jenkins, a former police officer, said he just used common sense - he told students he would hold them accountable for their behavior, and he handed out his cell-phone number to merchants and bus drivers. "I made myself a physical presence up and down the Ridge," he said.

Paul J. Fink, a psychiatrist and school district consultant, said principals like Jenkins were uncommon.

"What that principal has said is 'I'm taking responsibility for this,' " said Fink. "We don't have enough of that - strong adults to set an example for the kids. . . . The kids feel they have a license to get wild, and that's tragic."

Planning for the after-school rush involves more than positioning officers near buildings, said Golden, the school security chief. "I think you'll find a fairly high level of coordination," he said.

School police and SEPTA officers participate in the Philadelphia Police Department's weekly CompStat meetings, where the agencies share intelligence.

Every Monday in Northwest Philadelphia, police, school officials and community leaders hold a conference call and compare notes on neighborhood tensions.

"You can get a step ahead of the problems," said Eric Hardaway, a legislative assistant to State Rep. Dwight Evans (D., Phila.), who chairs the meetings.

Last week, district security officials were concerned about King High School, which had experienced a series of disruptive brawls the week before.

By March 5, the weather was clear and springlike - a recipe for conflict.

"Some officers would be happy if it rained every day at 3 p.m.," said Singletary, 14th District captain, as he cruised in an unmarked Ford.

As dismissal time neared, city squad cars and bike patrols moved into position around King and Germantown High Schools and several middle schools. All officers not working on a current job - including administrative officers - are under orders to activate at dismissal time.

"We have it down to a science," said Singletary, 46, a 22-year veteran.

At King, Whitfield of the school police force directed security personnel to roll 15 minutes before the 3:05 p.m. dismissal. Most of the school's 1,500 students exit out of two of the building's 40 doorways. About 200 to 300 students stay late for extracurricular activities.

The nearby Hope Charter High School, which serves about 400 students with histories of academic and disciplinary troubles, dismisses about a half hour after King to minimize the potential clashes.

Area businesses, however, say they still feel the deluge.

McDonald's, on Stenton Avenue across from King, employs a security officer to keep order at dismissal.

Even so, "there's still a huge crowd of kids that just sort of moves from the school across the street here like a big cloud of trouble," said the security officer at McDonald's, who would only be identified as Phil.

Several students said they are unafraid.

"I don't have any problems," said Brianna Randall, 14, a ninth grader. "I just be myself. I don't really worry about no drama."

While police at King were quelling the sidewalk quarrel between the two boys and the adult, the radio in Singletary's patrol car reported another "drama" unfolding two miles away at Germantown and Chelten Avenues.

A crowd of 70 Germantown High School students encircled two feuding girls in the heart of the neighborhood's business district. School security officers and green-vested volunteers from the Germantown Clergy Initiative intervened.

"We squashed it immediately, before the first punch was thrown," said the Rev. LeRoi Simmons.

Simmons and other activists began standing watch on Germantown Avenue in 2004 after a 15-year-old boy was shot outside the school.

But, as with many town-watch organizations formed in the aftermath of a traumatic event, community involvement has waned. From the initial 85 people trained in 2004 to patrol the school dismissals, only a "remnant" remain, Simmons said.

"People have short memories," he said.

At Olney Terminal, transit officers moved through a crowd of youths like border collies managing a herd.

"You just have to keep the kids moving and try to defuse situations as you see them developing," said SEPTA Police Lt. Mike Gritsko.

Students from seven public and private high schools board the subway and buses at the busy terminal. Citywide, 55,000 Philadelphia students use SEPTA every day, according to the agency.

Police watch for gangs maneuvering to target robbery victims. "Today it's iPods, and two years ago it was cell phones," said Gritsko.

Some students hover near the officers, silently seeking protection. Many recognize the officers, even those working undercover.

SEPTA Officer Kevin Fant, wearing a down vest, a black skull cap and carrying a black book bag, looked more like a college student as he took the stairs into the Broad Street line.

A teenage boy, whom Fant had lectured previously about improving his behavior, reached up to shake his hand. "He used to give me trouble," Fant said.

"We know the problem ones, so they recognize our faces," said Fant, who rode the line to Girard Avenue without encountering trouble.

The proliferation of charter schools has complicated the transit officers' work, creating more locations from which students emanate during dismissal. SEPTA's switch this year from tokens to weekly passes for students has also added a wrinkle - troublemakers now have unlimited access to stations.

Even with the added city police last month, transit police can't cover everything underground - SEPTA runs 258 subway cars on its two lines when schools let out, more carriages than the agency has officers.

"You'd have to have something like an army to cover every station and car," said Richard J. Evans, SEPTA police chief.

Across the city, many police were on the move at 3 o'clock.

The sidewalks outside South Philadelphia High School at Broad and Snyder Avenue bristled with city and school police officers. Among them was Sgt. Fred "Buck" Henry, patrol supervisor for the district's school police.

"This is just one corridor we come to every day," said Henry, who supervises 16 two-officer mobile teams. All told, the school district employs 430 officers and another 165 school security personnel.

The mobile patrols are dispatched according to need.

"As time gets close to dismissal, I get the calls," said Henry, 62.

That day, school police positioned themselves outside one expected hot spot - E.W. Rhodes High School in North Philadelphia, where two groups of girls had fought the day before.

A call came from Stetson Middle School at B and Allegheny Avenue. Earlier in the day, a student had been arrested with drugs, and the angry family had come to the building and a crowd was forming outside.

Henry grabbed the radio: "Disregard Edison High School," he told one of his teams. "Get down to Stetson."

He also received a call from Blaine Elementary in North Philadelphia, where officials feared the reappearance of a group of young men who gathered the day before.

But no units were available.

"It's a chess game," Henry said. "Without the help of Philly P.D. it would be really difficult."

At 4 p.m. in Northwest Philadelphia, Capt. Singletary breathed a sign of relief.

For a warm day, it had been remarkably quiet.

There's no telling what might have happened without the show of force.

"It's sad this is what it comes down to - a heavy police presence when kids get out of school," he said. "But the kids need protection."

Inquirer staff writer Vernon Clark contributed to this article.