Nearly 300 citizens packed the Oxon Hill Junior High School multipurpose room last week for hearings on the proposed master plan that would serve as a guide for development in southwestern Prince George's for the next 20 years.

The plan proposes partial development of the Potomac River shoreline, extension of I-295, the widening of several major roads and construction of a major new highway. More than 70 citizens signed up to speak last week and another 60 were scheduled to speak at a hearing this week.

Two state delegates showed up with noisy bands of followers.

State Del. Charles Blumenthal (D-25th) and his brigade brought large white placards with red letters announcinig: "Save Smoot Bay, Don't Commercialize" and "No I-295 Extension."

State Del. Elaine Sheehan (D-26th) and members of her organization, Citizens for the Branch Avenue Metro, passed out pamphlets calling the planned Rosecroft Metrorail alignment an "environmental disaster" and explaining why a Branch route would be cheaper and better.

Civic association leaders and homeowners also spoke, generally praising the plan as a reasonable solution to the problems of development and traffic congestion along the area's overloaded throughways. Lawyers in well-cut three-piece suits took their cases to the crowd, most arguing for more high-density development of the area.

But when Dr. Mervin Strickler, chairman of the citizens advisory committee for the Subregion VII master plan, closed his statement to the audience with the comment, "It's our plan and it's your plan," Blumenthal's supporters sitting in front of the podium shouted, "No it's not. No it's not. It's not our plan."

The hearing, the second held on the plan, attracted more supporters than opponents, however. Members of the citizens' advisory committee had succeeded in orchestrating support for the plan in their communities.

The committee members, many well-known community leaders themselves, worked with the staff of the Maryland-National Capital Park and Planning Commission on the plan for five years.

George Price apparently was voicing the feelings of many of his fellow advisory committee members when he told the audience, "Development in Subregion VII cannot be stopped. Planning must include adequate roads for the future lest residents find to their sorrow that they are blocked into their driveways."

Blumenthal contended, however, "This is probably the most controversial plan I've ever seen.

"You talk about creating jobs at employment centers in the subregion. Well, we think employment centers are just another name for places where you put hot dog stands and used-car lots."

Blumenthal also lashed out at the plan to extend I-295.

"What you're talking about doing is destroying homes and disrupting the lives of the people who live in my district," he said.

Adding that he didn't want to be a man who had complaints and no solutions, Blumenthal laid out an alternate plan for a route through his district, which he said would not disrupt as much of the area.

Until now, though, the proposed Metrorail alignment to Rosecroft has drawn the most vehement opposition, and that has come largely from Sheehan's organization. Sheehan said that Citizens for the Branch Avenue Metro has more than 4,000 supporters and quite a bit of organized civic support.

"It's just amazing how things have come together in the last two months," said Sheehan. "Most people just didn't even know that the Rosecroft alignment was being supported by the County Council and the planning commission. But now we have the facts and we can show that this alignment is more expensive, will serve fewer people and will destroy people's homes."

In their organizational pamphlet, her group claims that 15 times as many people work along the Branch Avenue corridor as along the Rosecroft alignment, and that the latter would cost $10 million more to run each year because of the ridership disadvantage.

Calling the Rosecroft route an "environmental disaster," the pamphlet goes on to note that the alignment would run through the Hillcrest Heights Recreation Center, come within 100 feet of homes in the Hillcrest Heights subdivision and cannonball through the St. Barnables Church property.

"Much of the information in that pamphlet is patently untrue," said Helen O'Leary, a member of the citizens advisory committee for the plan. "There are 4,271 dwelling units within a half-mile of the Rosecroft route and only 2,514 within walking distance (a half mile) of the Branch Avenue alignment."

O'Leary also said the information on the yearly operating deficit for the system and the environmental impact was exaggerated.

"The operating deficit for the Rosecroft rail would be $3 million less than that of Branch Avenue, and though the feeder bus deficit would be $8 million, the bulk of it covers buses in the district," she said.

Both sides stand steadfastly by their facts and it appears that the County Council will have to be the final arbiter in the dispute. The debate over the Metrorail alignment has been a long and bitter one, dating back to the early 1960s.

Last Year, in an effort to put a lid on the controversy, the County Council voted 9-2 for the Rosecroft alignment. Now in a resurgent movement, the Branch Avenue line supporters, backed by area developers and other industrialists, have mounted a last-ditch effort to reverse the decision.

No one seems to know what the council will do when it reviews the subregion VII plan a few months from now. Sheehan said her group needs only two more votes on that body to reverse the decision. "While we're optimistic, we know that something big will have to happen in the next month for us to win."

O'Leary says she also is uncertain of the outcome. "I've heard that there are two swing votes on the council," she said. "But it would be tremendously embarrasing if the council reversed itself. I would hope that they would just be ashamed of themselves."