With no fanfare from the Metropolitan Transit Authority, New York’s first computer-controlled train carrying passengers rolled out of the Rockaway Parkway station early Monday morning, transit officials said.

The MTA activated the long-awaited Communication-Based Train Control system on two trains on a stretch of seven stops along the L line in Brooklyn, a spokesman for the authority, Charles Seaton, said.

This is the “shadow mode” portion of the testing, the editor of the monthly trade publication Railway Age, William Vantuono, said. Transit officials are quietly testing the technology on trains with few actual passengers.

The trains are under the computer’s influence between Rockaway Parkway and Broadway Junction. Tests are scheduled to take place from midnight to 5 a.m. every night this week.

The motorman, who ordinarily has sole discretion over the train, has no decision-making responsibilities. The motorman still drives the train, but he takes all his orders from the computer, including how fast to go and when to slow to a stop. The next phase of the system’s development will remove the motorman’s driving responsibilities altogether.

“It’s been a long time coming,” the director of City College of New York’s Transportation Research center, Robert Passwell, said. Subway systems in Paris, London, and Washington, D.C., already use similar technology, he said. Mr. Passwell is the former head of the Chicago Transit Authority.

When implemented, an off-train computer will control all the trains operating on the L line by radio. A motorman will still ride the train to control the doors and tell the computer when it is safe to leave the station.

New York is one of the last major metropolitan cities to begin using computer-based control of its subways. Since 1904, trains have run on a highly effective – yet antiquated – system called Automatic Block Signals, Mr. Vantuono, said.

“This new technology is the direction the world is going,” he said. “In terms of safety and capacity, it will be an improvement over existing technology.”

The trains operating on the new system are in radio contact with the computers at transit headquarters on Jay Street, which closely monitors each train’s speed and distance from other trains. If a train for some reason lost its radio signal, it would enter failsafe mode and return control to the motorman.

Mr. Passwell said one important change under the computer-controlled system is that when a train gets held up it can be managed in real time, compared with the ad hoc way delays are now handled.

The trend of designing technology that deals with problems instantaneously is increasingly used throughout the city’s agencies. Police Commissioner Raymond Kelly unveiled last summer the “Real-Time Crime Center,” a help desk for detectives to discover patterns of crime quickly. The city is on the verge of creating a pilot program for what could become a citywide wireless network for personnel to access information about emergencies and crimes at high speeds.

Leaders of the Transit Workers Union Local 100 have in the past strongly criticized the program as being potentially dangerous and likely to result in job losses. A spokesman for the union would not comment yesterday.

Mr. Passwell said that while he is a fan of the new system, he feels the MTA’s reasoning for its implementation is not correct.The MTA has touted the technology as a way for the agency to save money, but he said it is more important to think of it as a way to enhance the quality of transportation for the millions of straphangers who ride the trains every day.

The city’s computer-controlled system is largely based on technology used in Paris’s subway system called Meteor. The German electronics company Siemens designed the French system and was part of a joint contract to set up the MTA’s version, along with Union Switch & Local,and RWKS Comstock. The Meteor system is “driverless” and uses an inductive loop similar to the kind used at traffic lights to detect when a car is waiting to cross instead of radio signals. The system in Washington, D.C., communicates to the train through the rails.

Next up on the list for adaptation is the Flushing line, no. 7, which already has most of the infrastructure modifications to the tracks in place.