According to the Farecard gates, 153,000 people entered the Metro subway on Jan. 20, but only 143,000 came out.

On an average day, about 6,000 people a day disappear into the Metro system, never to be heard from again, according to Farecard.

"It's kind of ridiculous," said Delmer Ison. Metro's secretary-treasurer. "It just means the machines are not doing their job." It does not mean, he insisted, that Metro is losing fares from 6,000 people a day.

But Metro is losing money both beacause of problems in the Farecard programs and because some people have figured out how to cheat by more devious means than just jumping over the gates, Metro officials concede.

The amount of loss, according to Nicholas Roll, Metro's assistant general manager fro transit services, is "insignificant" But neithe he nor Ison nor anybody else at Metro knows exactly how much it is.

But things like this, either witnessed by or related to Post reporters, cost Metro money:

Rider enters at Sivler Spring, rides to Farragut North during morning rush hour. Fare is supposed to be 75 cents . Farecard machine deducts only 40 cents from the Farecard. Net loss to Metro: 35 cents.

Big crowd overwhelms gates at Pentagon during evening rush hour. To ease situation, Metro attendant offers to take "exact fare" Farecards - those wit only the cost of the last ride remaining - and let patrons bypass the Farecard gate. Dozens of people are on the honor system now. If they took a 50-cent ride, from Capitol South, for rxample, but only 40 cents left on their Rarecard, they get out for 10 cents less and nobody knows.

(Monday afternoon, an attendant let 50 people through that way, then inserted all their Farecards into the exit gate. Only two were rejected for insufficient fare value).

There are ways to cheat made possible by the fact that Metro decided to permit joyriding. Within a four-hour period, if the machines are working properly, people can enter the subway, ride around, then leave for only 40 cents.

As Metro riders know, those are not only the problems with the $53.2 million Farecard-system that million Farecard -system that Metro has purchased from Cubic Western Data, a subsidiary of the San Diego-based Cubic Corporation.

According to figures obtained from Metro, as many as 34 of 242 Farecard vending machines may be out of order an any one time. That's 14 percent. The average is about 12 percent. Neither of those percentages reflects himself short-term without having to call a repairman. A short term problem in the rush hour can mean a long line, however.

The Farecard vending machines are the least reliable piece of equipment in the Farecard system.

The Farecard gates are second. About 5 percent of the gates do not work at any one time, according to the Metro statistics. But again, that does not include the number of times an attendant has to dig into the gate to retrieve someone's bent Farecard.

And that does not include the strange disrepaney between the number of people who count as entering. It is also the exit side of the system that collects the revenues, according to Ison.

Thomas Turttle, the Cubic Corporation's manager for the Metro contract, said yesterday that Cubic is continued to study all the Metro problems. He dealt with them one at a time:

The 6,000 extra people problem is , he said yesterday that Cubic is continuing to study all the Metro problems. He dealt with them one at a time:

The 6,000 extra people problem is, he said, a "freak". "There is a problem in some parts of the computer. We have developed a new program we think will solve it and it will be installed soon." In the meantime, he said, "I absolutely do not believe that Metro is losing fares."

Cubic believes that a new order of blank for cheating the possibility of cheating. Through "a comedy of errors," Tuttle said, a shipment of those new Farecard blanks has yet to reach San Diego from Washington. "Once we get that Farecard, we can analyze it in about three hours," he said.

If a ride is undercharged for a long ride, then it is a "human error", Tuttle said. Sometimes in maintenance and sometimes in new installations the wrong code is placed in the small computer in each Farecard gate he said. That can result in the wrong fare being charged.

Metro's Roll recently visited Cubic's operation in San Diego. He insists the performance of the equipment is improving steadily. But "we're not satisfied."

Roll also said that Metro has adopted a "customer is always right" approach to Farecard problems.Even when station attendants think a customer is trying to beat the system, they ultimately let them through without paying extra money.

For one thing, there is no "reader" at the stations so attenants can see what the magnetic strip on the Farecard really says. Such a "reader" is being considered, according to Metro officials.