EDITORIAL : WATCH THOSE PRIORITIES LOSS OF SUBWAY FUNDS MUST NOT BE ALLOWED TO IMPACT BUS RIDERS.

THE Metropolitan Transportation Authority suffered another jolt last week when a congressional panel approved only $70 million - less than half the federal funding the MTA had requested - for the next year of Metro Red Line subway construction.

We - and about 1 million passengers who ride MTA buses every work day - certainly hope that the transit agency won't respond to the bad news by imposing a domino-like cascade of pain that culminates in worse bus service.

MTA Chairman Larry Zarian (who interpreted the federal grant of $70 million as a glass half-full) conceded that reduced federal funding could slow the pace of subway construction. But he insisted: ``This does not mean we are not going to build rail, and it certainly does not mean that our bus program will be impacted.''

That statement was welcome. But based on past experience with the MTA - and without doubting Zarian's integrity - the public may want to wait and see how the MTA responds to this challenge. After all, there's more lobbying pressure for big-budget subway contracts than for upgrading or even maintaining bus service.

Admittedly, the MTA board voted this year to spend $10 million for bus service improvements for the transit-dependent communities in this sprawling region. But even more must be done. Too much has been spent subsidizing rail passengers to the detriment of bus passengers.

The Southern California-based Reason Foundation recently issued a report that found for every taxpayer dollar spent on MTA bus riders, $64 will be spent to subsidize rail passengers. Meanwhile, those bus riders must make do with some of the most overcrowded buses in the nation, the study said.

Meanwhile, the MTA continues spending heavily on its go-nowhere subway, which was based on unrealistic funding expectations and overly optimistic ridership forecasts.

But as troubled as the Red Line project has been so far (it has been plagued with delays, cost overruns, subsidence, questionable construction work and contracting irregularities), things would become even worse if funds are bled away from programs needed to operate buses and maintain reasonable fares.