THE SURGE.(high security in New York City subways)

Last Wednesday, shortly before four in the afternoon, Lieutenant Bruce Simonetti left his office, at Transit Police District 2 headquarters, underneath Canal Street, boarded the A train heading downtown, and disembarked two stops later, at the Broadway-Nassau Street station. Twenty-four police officers--eight from Manhattan, eight from the Bronx, and eight more from Queens--were waiting for him there, along with three sergeants, in front of a newsstand that proclaimed, in large block letters, "God Bless America."Another eight cops from Brooklyn were expected, but when, after about ten minutes, they hadn't shown up, Simonetti gave the order to move out. The officers, who were all wearing bulletproof vests and carrying what are known as "escape masks,"pushed through the gate, and took the No. 4 train up to the Brooklyn Bridge stop.

Simonetti, who has been with the N.Y.P.D. for eighteen years, is a compact man with thinning brown hair and a friendly, oval face. "I love this type of work,"he said on the way uptown. "I'm a people person. I love to talk."In normal times, transit police deal mainly with pickpockets and thieves, or "lush workers,"who prey on anyone unfortunate--or drunk--enough to fall asleep in the subway. But these, of course, are not normal times. Nowadays, officers are assigned, twenty-four hours a day, seven days a week, to stand guard at each end of the city's fourteen under-river subway tunnels to make sure that the tunnels don't get blown up. And every weekday morning at eight o'clock and every afternoon at four, thirty-six cops gather at a subway station in lower Manhattan for what is known as a "surge."

"What we're doing is very similar to what the military does, and to what Israel has been doing for many years,"Simonetti explained. Every surge starts with all thirty-six officers going to the same station--the particular station changes each time--and then, after half an hour, dividing up, so that eighteen continue on together to the next station, while the other eighteen split up and go to two different stations, and so on through four stops. "Anybody who's bad and wants to watch to see if we're creatures of habit, we're showing them we're not,"Simonetti said. "We're creating confusion.”

On Wednesday afternoon, when the officers arrived at the Brooklyn Bridge station, Simonetti sent the groups from Queens and the Bronx over to the downtown side, while ...