WHAT MARY Margaret Whipple is doing to the city's Metrorail system flies in the face of bureaucratic tradition. No sooner did she become chairman of the board at Metro than she decided that even when a good thing isn't broken it can stand some fixing -- specifically, she determined that the subway's customer services could be improved. But then Mrs. Whipple disregarded the time-honored method for deciding what could be done -- an expensive and time-consuming outside consultant's study. Instead, she simply issued an invitation to riders to submit suggestions. About 1,800 have come in, and now the board is going ahead and adopting some of the best of them.

Already, the board has approved installation of pay telephones on station platforms. This will be done at no cost to the system and is expected to generate $150,000 a year in revenue for Metro once all the phones are in place. Other changes likely to be made include better lighting in the stations, more signs, more Farecard vending machines that accept $10 and $20 bills, a 24-hour telephone assistance line for riders, mailboxes at station entrances and ways for riders to use credit cards to buy Farecards.

Officials also have approved a suggestion to provide a transit system information display at the bus stop at 11th and H streets NW near the Convention Center. Still other ideas likely to be adopted include: selling the family/tourist pass at all stations instead of just at one station and nine sales outlets; providing information at bus stops about route numbers, schedules, maps and other basics of bus travel; lighting and phones for bus shelters, with a hot line to Metro; indicators showing what color train is due next on the track; and providing some Spanish language training for bus drivers on routes with substantial numbers of Spanish-speaking riders.

Every one of these proposed improvements is simple and inexpensive. None calls, in the more familiar government fashion, for a pilot project, to be evaluated by a date uncertain and at a cost to match. Where are standards, anyway?