He could be the subject of a musical. Call it "The Bus Man" and, to paraphrase Meredith Willson, he would sing: "We've got trouble in Capital City. Spell it T-R-A-N-S-P-O-R-A-T-I-O-N."

To be more precise, lack of public transportation to Capital Centre. And the Bus Man thinks he can rid the Centre of this headache while embarking on the first step toward building a bus empire that would provide bona fide competition for Metro.

Go ahead and dismiss the Bus Man, Posey Preston, as another dreamer, especially after considering he owns only one, formerly "hot" 1956 bus, and his treasury is as empty as his bank account. People have been discounting his ideas since he first devised the concept he now calls Suburban Transit Co.

But don't expect him to go away.

"Posey Preston is one persistent person," said Capital Centre President Jerry Sachs, who has learned first hand about Preston's unflappable nature. "I don't think his idea is feasible but you have to hand it to him. He believes in it with body and soul."

So much so that he bought an ad last week in The Washington Post. It cost him, he says, $1,700, which he paid for by selling two of his three buses. The ad took the form of a letter to Centre owner Abe Pollin, asking for a meeting to discuss his ideas.

"I had been told I could never see Mr. Pollin," said Preston. "I was desperate. It seemed the only way to get his attention."

He was correct. By that afternoon, a meeting had been set up and Preston was told the Centre would consider trying out his transportation ideas on an experimental basis - if he could supply Pollin with a detailed plan of operation.

"It was," said the Bus Man, "music to my ears."

Preston's concept is simple. Set up a bus system with stops in all parts of the Washington metropolitan area and operate it anytime the Centre opens its doors. Preston would buy tickets from the Centre at a group rate - roughly half price - and sell them to bus riders at full price.

Passengers would pay nothing else for the round trip, except for those events where discount tickets were not available. Then it would cost $3 each to use the bus.

"They don't think I can make money this way but I know I can," said Preston, who, at 27, works full time at trying to lauch his idea. "Wouldn't you go to the Centre on a bus when the cost of the transportation was absolutely nothing?"

Preston is convinced there is profitable market out there, full of "people that are frustrated by traffic jams around the Centre and frustrated by not being able to get out there at all unless you have a car."

He has already tried to tap that public. Surburban Transit buses have transported fans to Centre events for almost three years. Despite breakdowns, bad weather, legal problems and lack of funds, Preston thinks he has proven his idea can work. But not without more buses, better promotion and "a good-sized loan" - of Abe Pollin's money.

Sachs disagrees. When the Centre first opened, it had a contract with Metro to provide buses to events. The result, said Sachs "was a disaster. We had to make up the difference to Metro on the nights they didn't have enough riders. We took a large financial bath.

"We hardly ever get any complaints about lack of public transportation out here. I am sure there are people who would like it, but the problem isn't even on our list of major headaches. I just don't think there is a market out there big enough to make Posey's idea work."

Preston, however, says Metro "went about the whole thing wrong. They had express service. I'd have regular bus stops all over the area. People would know we were coming and they'd depend on us.

"There are a lot of people in the inner city who want to come to Bullet games but can't get out there. They are missing out on a lot of fans because they don't have a bus system."

Preston has been obsessed with his Suburban Transit concept since the night his car broke down in the Centre parking lot and he had to walk home 16 miles.

"If there was a bus around, I wouldn't have had to walk," he said.

He became the owner, mechanic, driver, public relations man and sole financial backer of the fledgling operation. He purchased mid-1950s buses - "do you know how much a new bus costs?" - and scrounged for parts and a break. He turned Capital Centre into his office away from home, undertook what he calls "an education by the seat of my pants," wrote a short book about his ideas and dreamed.

He dreamed of a fleet of 51 buses packed with sports fans flocking daily to Capital Centre. He dreamed of a daytime commuter bus system more efficient than anything Metro can produce. And he dreamed of making a success of a concept others thought was foolish.

"Abe Pollin is a very sympathetic person," said Sachs. "He believes in giving someone a chance. Posey has worked hard and he deserves that chance. He has done all he could with his limited resources."

Sachs says the Centre has received a number of complaints about Preston's service. Some of the difficulties have been caused by his equipment, which constantly shows its age. But Preston feels fortunate just to have even one bus.

"I bought the one bus I have now from a guy who didn't have papers for it," he said. "The last thing I needed was a hot bus. So I went to Philly, tracked down the guy who used to own it and got things straightened out."