The Environmental Protection Agency and citizens' groups have condemned a federal study of the impact of CSX Corp.'s plans to sell a strip of railroad property on areas near the 11-mile right-of-way running between Georgetown and Silver Spring.

The EPA's Philadelphia regional office said in a recent letter that the study did not contain enough information and did not answer some of the agency's earlier questions.

The Interstate Commerce Commission, which regulates railroads, prepared the environmental impact statement. It's one step toward deciding whether to grant CSX's request to abandon the right-of-way. A spokesman said that although the commission has "some concern" about the EPA's opinion, the ICC will not prepare a supplemental environmental impact statement, as the EPA suggested. The ICC also will not delay the abandonment decision, which is expected before the end of the month, the spokesman said.

Organizations representing District and Montgomery County residents who live near the rail line, known as the Georgetown spur, also called the environmental statement deficient and asked the ICC to perform more studies. Anthony Czajkowski, of the Greater Bethesda-Chevy Chase Coalition, said the group would consider court action "if we feel the ICC has not followed all the federal statutes."

An EPA official, however, backed away slightly from the agency's position, saying the ICC "has met its obligations under the law" by merely preparing the impact statement.

The dispute is the latest chapter in a long, often acrimonious debate over what to do with the right-of-way, a strip of land of varying width that passes through some of the most valuable property in the Washington area. About one-third of it goes through the C&O Canal National Historic Park.

Trains on the line delivered coal to a General Services Administration heating plant at 29th and K streets NW, which supplies heat to 120 federal buildings. Those trains stopped running more than a year ago; the coal now comes by truck from Bladensburg to the Georgetown plant.

CSX Corp. wants to abandon the line because it no longer makes money, according to railroad officials, who made it clear they expect to sell the property for a high price. The proposed sale touched off concern among National Park Service officials and among residents along the right-of-way that the land would go to developers who would build houses or offices on it.

Prospective buyers and CSX appear to be far apart on how much the land is worth. Although representatives of both sides refuse to divulge figures, a reliable source said the railroad company has asked $60 million for about 84 acres in Montgomery County, while the county government has offered $6 million. Railroad officials said more than a year ago that they wanted $15 million for the land in the District.

National Park Service Director William Penn Mott said the opportunity to use the right-of-way for hiking and biking trails is "extremely valuable."

He said, "It's something we want to make sure happens."

Another park service official said the agency has commissioned its own appraisal of the District property.

Only about half a mile of the Georgetown spur is still used, according to Lloyd Lewis, a CSX spokesman. Trains deliver supplies from the main rail line to a Silver Spring lumber company on the branch line, he said.

The Montgomery County government would like to use part of the property for a cross-county commuter rail line and for recreational trails, while the National Park Service has said it wants to incorporate much of the land in the District into the C&O Canal park. Most residents along the right-of-way favor leaving the property as park land and recreational trails.

Arlington County, which buys water from the District's Dalecarlia reservoir, is considering using a section of the property as one of three sites for a new pipeline. The reservoir and the offices of the Defense Mapping Agency abut the right-of-way. The mapping agency reportedly wants to build a road on the rail property to its parking lot.

The environmental impact study, which included archaeological investigation of prehistoric settlement sites, took more than a year. The EPA said in its letter to the ICC that the final statement does not contain enough information to demonstrate whether the railroad company's proposals pose "serious threats" to the environment, despite an EPA request for more detailed plans.

ICC officials failed to address "many of the concerns and issues" raised by the EPA after environmental officials studied a draft of the statement earlier this year, according to Jeffrey M. Alper of the EPA. Alper, chief of the compliance section of EPA regional headquarters in Philadelphia, made the comments in a letter to Carl Bausch, of the ICC's office of transportation analysis. Alper's letter urged the ICC to wait until plans for the property have been developed, so that the commission could decide how to reduce environmental damage such plans might cause.

The environmental statement lists the types of permits CSX intends to request for salvage operations, such as removing tracks and bridges, when it abandons the property. It does not, however, provide details on "the types of mitigation measures required by these permits ... ," Alper's letter said.

The ICC has agreed to answer the EPA's comments and questions by letter before making its final decision on the railroad's abandonment request, Alper said.