It's Metro Day here at the ranch. From several dozen letters about bus and subway service here, few of them friendly, I've culled a sample of what bothers people most, and most often.

For simplicity's sake, I've decided to present my mother lode in question-and-answer form. In each case, the As to the Qs have been provided by Cody Pfanstiehl, Metro's relentlessly cheerful public relations director.

Clip-and-savers are hereby advised to sharpen up their scissors. Like a comet, these nagging questions and official replies will pass this way again, but probably not for a while. If you'd like to send your cousin George the official Metro explanation of air conditioners that don't condition, this is your chance.

Question (from George Cunningham of Northwest): Why don't air conditioners on buses work? And please don't tell me because passengers open the windows. Surely a powerful-enough air conditioner can be built.

Answer: "American industry has not come up with a bus which can be purchased for heavy city operations that can take the extreme heat. . . Believe me, Washington is not alone in this dilemma. . .

"Monitoring and reports will not directly rehabilitate some very crummy garages we inherited from private companies (and) will not increase the budget given to us by the eight local governments who determine our budget so we can hire maintenance people in large enough numbers. . .

"We don't blame him (Cunningham) for being angry. We are even more angry because we have to make do with what we get."

Question (from Aili Bell of Alexandria): Why do Blue Line passengers refuse to relinquish clearly marked priority seats to people who obviously need and deserve them?

Answer: "Priority seating is a courtesy, not a law. It is a problem in any city. . . We urge all people to be kind to all people, but if a bus operator is 5-foot-1 and the able-bodied person sitting in the seat there is 6-foot-11 and 300 pounds, a suggestion to move may not be heeded."

Question (from Donald Ingerman olf Crofton): Why isn't there better enforcement of the compact-cars-only policy in one of the parking lots at the Landover subway station? The "body count" one morning early in July included a Chrysler, a Caprice, an Impala and two vans. What gives?

Anwer: "Our agreements with . . . local jurisdictions call for parking lots to be looked after by the local police departments, like parking lots at grocery stores and theaters and such. But most local police officers have more meaningful things to do most of the time than look for big cars in small spaces. Our Metro Transit Police try to do what they can, but the same thing applies."

Question (from Adele Nusbaum of Northwest): Can't anything be done to make standees move to the back of the bux?

Answer: "This is one of the oldest problems any bus operation in the U.S. has. Bus operators have been trying to solve it for years. Signs don't seem to do any good. The bus operator often gets it in the kisser if she/he suggests moving back.

"The AAA's Glenn Lashley said he could solve it. Make the bus look like the inside of a church.

"'Then,' says Glenn, 'everybody will sit in the back pew -- and you will know who the sinners are.'"

Metro Postscript: First it wouldn't take your dollar. Then it took your dollar and wouldn't give you a Farecard. Then it decided to break entirely -- and keep on breaking. To put it mildly, Reliability and Farecard have not been kissing cousins.

Lately, however, Farecard has gotten fouled by froth.

Apparently if you manage to get enough saliva on a Farecard, either the accounting code on the magnetic strip gets bollixed, or the card warps to the point where it won't pass through the fare collection mechanism.

Metro is so concerned by this latest wrinkle that it is considering coating Farecards with a terrible-tasting substance, so card-chewers will mend their ways.

But which substance?

Among early nominees: cloves and castor oil.

Do you have a favorite? I volunteer as collector.Anything plausible is welcome.