Some people were angry and many more were confused on the first day of changes in more than 150 Metrobus routes yesterday, but the regional transit system responded with its smoothest inaugural to date.

Not one single train broke down in either the morning or evening rush hours, and the thousands of Maryland and Northeast Washington commuters who found themselves riding the Metro subway's red line because their buses didn't go where they used to could not complain about the performance of the trains.

More than 150 Metrobus routes were changed yesterday, primarily to eliminate parallel bus and subway service created two weeks ago when Metro extended its red line 5.5 miles from Rhode Island Avenue to Silver Spring in Montgomery County.

At the same time, Montgomery County vastly expanded its neighborhood small-bus network, called Ride-On, and the county buses carried at least 3,500 people to the Silver Spring Metro station alone yesterday.

Jim S. Tueve, who works downtown and lives in Silver Spring, was one of the happy ones yesterday. "I used to pay $58 a month to park my car downtown and that doesn't count the gas or time," he said. "Now I can walk three blocks to a Ride-On and I pay $40 a month for everything." He takes the Metro from Silver Spring to Dupont Circle.

But Andrea Edmond, a D.C. job placement specialist, called the changeover "atrocious." "They don't give me an alternative," she complained. "I don't like it one bit, and if you want to know, I'm late for work."

Edmond was at the Silver Spring station yesterday and had discovered that her express bus, the one that used to go directly downtown, now stopped at the Metro station and went no further.

Virginians and residents of Southeast Washington and southern Prince George's County made similar discoveries last August and September when Metro started redrawing the bus map as the subway lines expanded. In the past seven months, two-thirds of Metro's 750 bus routes have been changed so buses can feed outlying subway stations.

Yesterday will also be a record day for Metro subway ridership, although the numbers will not be available until today. By 9:30 yesterday morning, however, a total of 10,773 people had entered the four new Metro stations on the red line -- Silver Spring, Takoma, Fort Totten and Brookland.

That's about double the number of people who were using the subway by that hour on Feb. 6, the day the Silver Spring extension opened. On that day, however, the buses were still running their old routes.

Metro has predicted that with the bus turnback at the stations, the trains will be carrying about 170,000 people a day by March 6, and 180,000 people a day by June 30. San Francisco's Bay Area Rapid Transit (BART), the other new subway system in the United States, has more than three times as many miles of track in operation (70 vs. 23) and is carrying about 150,000 people a day.

Nicholas Roll, Metro's assistant general manager for transit services said he was delighted with the system's performance yesterday."If I have any complaint, it's our graphics," he said. "We need immediate fine tuning there."

Roll had noticed, as had his passengers, that it is difficult to find the exact bus bay or the quickest route to the train station from the signs presently available.

Metro and Montgomery County personnel were posted at all the new stations yesterday to assist commuters, many of whom were wandering aimlessly in tearch of their buses, transfers clutched in their hands.

H. I. Cogdill, the chief street supervisor for Metrobus, a man who once operated a trolley and who knows all 750 bus routes, stood outside the Silver Spring station last night, and in a virtuoso performance directed 15 people to the correct bus in the space of one minute. He did the same thing at Rosslyn back in August.

Montgomery County officials estimated that the Ride-On system carried 3,500 people to Silver Spring station by 9:30 a.m. That would be more than half of the 5,335 who had boarded there.

"We were getting standing loads from streets that never had bus service before," said Ed Daniel, county transportation planner.

The Farecard machines seemed to work well during both rush hours, although many people had questions about their operation. Others, however, had prepared.

One commuter, who was sprinting from his bus to the train platform at Fort Totten, said, "I've had no trouble. I knew the bus was coming here and I bought a Farecard last week." Farecards are the magnetically encoded, wallet-sized tickets passengers must use both to enter and exit the subway.

Previous Metro openings have been marred by full-scale train breakdowns and balky Farecard equipment. There were two minor breakdowns before the morning rush hour yesterday on the blue line. The only problem on the red line was a signal near the Takoma station that persisted in displaying a red light when the tracks lay in a green condition. Trains were forced to operate at less than 15 mph through that section.

D.C. School Board member Betty Ann Kane organized a small protest of mostly private-school students to stand outside the Brookland station yesterday morning and protest the lack of cut-rate rail fares for school students. The District does provide 10-cent bus fares for school students.

Kane said both the District government and the Metro Board were dragging their feet. Essentially, both District and Metro officials agreed, Metro will provide any cut-fare plan the District wants to pay for. "We hope to have an abuse-free plan in place by the beginning of school next fall." D.C. transportation director Douglas Schneider said.