Just in case several recent news items about, or related to, Metro may have escaped the eye of a vacationing bus or subway user, there are some developments worth knowing about. One comes from Los Angeles, where the news for riders is temporarily good: they're getting a fare break. The fare has just been cut from 85 cents to 50 cents, with authorities expecting a 20 percent increase in ridership. Should Metro do the same?

While discounts for the elderly or people receiving welfare assistance make good sense, experience indicates that lower fares do not automatically result in increased use by the public--nor is an increase in ridership automatically a good thing. There is another good old-fashioned factor to consider: quality of service. Unless the service is attractive, the mere lowering of a fare may not bring large numbers of disaffected riders back to the buses. Besides, unless the system has good equipment to handle more people--what if the increase is all for rush-hour service?--more riders may not be a plus.

In any case, now that the local transit systems face the elimination of federal operating assistance, the transit math involves tradeoffs: either you raise fares, raise taxes for subsidies, cut service or do all of the above--which is what Metro has been doing here. In Los Angeles, the dip in the fare is possible because the voters approved an increase in their sales tax to help pay for mass transit. At that, nobody there expects the lower bus fare to last beyond 1985, when at least $100 million of this sales tax revenue must go to building a rapid rail system --if there is federal financing aailable at the time.

On the subject of equipment, Metro has a little intramural problem of its own: the D.C. government is holding up construction of a $15 million central maintenance plant in Alexandria. District officials are raising questions about moving jobs out of the city into the suburbs. For a regional system in which most of the employees are based in the city, this narrow view from city hall has no merit. For that matter, Metro is supposed to be moving people to jobs everywhere, so why not within its own payroll? The new plant is sorely needed. The city should go along with the plan.

On another front, the subway was the scene of a homicide--the first in the system's six-year history. What is worth noting is that this incident, involving a scuffle between two 19-year-olds, could have happened anywhere--and when it happened where it did, a Metro transit officer was right there on the platform to make an instant arrest. Metro's record is exceptionally good, and this latest incident should point up what has been an effective effort to keep the subways as safe as any in the country.