Have no doubt that our Metro subway system has moved into the major league of the nation's transit industry. It now carries more passengers on a normal weekday than any but two U.S. transit systems, those in New York and Chicago, and it's closing in on the latter. In doing so, Washington has elbowed aside Boston and Philadelphia.

The first to call attention publicly to Metro's rising status was Fairfax County Supervisor Joseph Alexander, a veteran Metro board member, speaking at the recent ceremony marking 10 years of subway operation.

To flesh out and confirm Alexander's statement, Metro Scene got the statistics from the Washington-based American Public Transit Association. These figures for ridership last December apply only to so-called "heavy rail" systems: rail transit lines, chiefly subway or elevated, that have their own protected rights of way and load cars strictly from enclosed station platforms.

Ridership of "light rail," modern versions of yesteryear's trolley lines, is excluded, as is railroad commuter service. In addition to their heavy rail lines, Boston, Philadelphia and San Francisco have significant light rail and commuter service.

The New York subway was an uncontested No. 1, with 230 miles of route and 3,479,700 daily riders. Chicago was No. 2, with 100 miles and 519,900 riders.

Washington ranked No. 3, with 61 miles and 452,100 riders (a figure that, swelled by tourists, reached 469,912 recently).

Boston was No. 4, with 42 miles and 391,600 riders; Philadelphia was No. 5, with 24 miles and 359,000 riders; San Francisco's Bay Area Rapid Transit (BART) system, with 72 miles and a route pattern resembling a commuter railway more than an urban rapid transit system, was No. 6 with 215,900, followed by Atlanta, a 25-mile system opened after Metro, No. 7 with 203,000.

There was a huge gap between Atlanta and No. 8, Baltimore, also newer than Metro, which has eight miles of line and about 40,000 daily riders. A few systems are smaller. Reserve Officers' Director

He entered the Army as a private in 1943 and became a lieutenant in 1945 and a two-star major general in the Army Reserve in 1980, commanding the 88th Army Reserve Command for two years while working full time as the U.S. attorney for the northern district of Iowa.

Now that Evan Hultman has retired from the Army Reserve and is about to complete his third term as U.S. attorney, he is making plans to come to Washington. He's been appointed executive director of the 125,000-member Reserve Officers Association, and he plans to assume his duties in June. Hultman was the organization's president in 1981-82.

A resident of Waterloo, Iowa, the 60-year-old Hultman twice served as the state attorney general and was the Republican nominee for governor in 1964. Flags of All Nations

Quick! Syria's Embassy needed an extra Syrian flag to take for a national holiday observance at the United Nations. Where did it turn? To the Vista International Hotel, which routinely flies the national flags of foreign VIP guests. The loan was arranged by hotel security chief Leo Pardee and the flag turned over to Ambassador Rafic Jouejati during a brief ceremony.