Starting next month, Metro will give quarterly security training to more than 1,100 station managers, train operators and janitors, prompted by the bombings in London, transit officials said yesterday.

Currently, those employees undergo security training when they are hired. The subway's 469 station managers receive yearly refresher courses, and its 475 train operators must know security procedures in order to be recertified every two years.

But Steven A. Feil, Metro's chief operating officer for rail, said yesterday that the level of preparation is insufficient. "You can't have awareness training every two years if you're in Code Orange," Feil said. "It's not enough."

The decision comes after an episode on a Blue Line train last week in which transit officials allowed an unattended backpack to travel on a train through two stations before inspecting it. The incident sparked panic among riders, some of whom ran from the train, and raised questions about Metro's response to potential threats during times of elevated fear about terrorism.

Metrobus drivers get security training every two years when they are recertified, spokeswoman Candace Smith said. Since 2003, bus drivers have also been given "suicide bomber training," she said. Metro employs 2,538 bus drivers.

Metro's 204 janitors receive the least amount of formal security training. They are given information during orientation after their hiring. Feil said that must change. "Station managers, train operators, janitorial staff are all becoming part of our first response," he said.

Calls about suspicious packages have nearly quadrupled in the weeks since the London bombings. Between July 7 and 25, Metro received 131 reports about suspicious packages or people, Smith said. During the same period last year, the agency received 36 reports, she said.

Metro's investigation into last week's Blue Line incident continued yesterday, and officials said they had yet to take disciplinary action. In that case, passengers spotted an unattended backpack about 1:25 p.m. in the last car of a train at Federal Triangle Station. Some passengers fled the car and ran out of the station; others alerted the train operator.

The operator, who has been in her job for seven years, contacted Metro's central control and was ordered to inspect the backpack, Smith said. The operator walked to the last car to look at the backpack, which was on the floor in the aisle, and decided that it did not pose a threat, Smith said. She made that determination based on Metro's criteria, which includes checking for exposed wires, leaking fluid and vapors.

Satisfied that the bag was innocuous, the train operator returned to her cab and moved the train out of the station. Leaving the backpack untouched in the last car was mistake, Smith said. Two passengers who were interviewed said the operator announced that the train had been delayed at Federal Triangle because of a suspicious package and that police would "hopefully" board the train down the line.

Over the next several minutes, confusion ensued and concern grew among passengers. At Metro Center, at least one passenger got off the train and notified police officers on the platform of the backpack. Meanwhile, officials at Metro's operations control center received a report that a child had left a backpack on a train at Smithsonian Station and suspected it was the backpack on Train 401, Smith said. They directed the operator to continue down the line to the next station, McPherson Square, she said.

At McPherson Square, a rail supervisor held the train and ordered all passengers to disembark while the backpack was inspected and then removed.

"It appears the operator made an error in judgment after determining that the backpack was not suspicious," Smith said.

"Instead, she should have either taken it herself to the end of the line and returned it to lost and found, or handed it off to the station manager at Federal Triangle. She also apparently did not clearly communicate to customers on the train."

Armed Metro Transit Police have been more visible this month after the fatal bombings on a London bus and in the city's subway, and after a Blue Line incident involving an unattended backpack on a train.