Montgomery County Executive James P. Gleason charged again yesterday that the U.S. Department of Transportation is "paving the way to delete" from Metro's planned 100-mile system a subway line to Wheaton.

Gleason made the statement after reading a letter from Transportation Secretary Brock Adams to the Metro Transit Authority. In the letter, Adame outlined his understanding of an agreement he reached last week with metropolitan area officials to conduct a cost-cutting engineering analysis on the Wheaton line.

In a press conference after that agreement was reached, Adams had left a clear impression with reporters and area officials that the agreement included a commitment to build the Wheaton line.

But in his letter to the Metro authority, Adams wrote, "The decision on whether the (Wheaton) route is to be constructed, and its timing, will depend upon the success of (the transit authority) and its consultants in achieving a design . . . that can be completed at costs significantly lower than currently estimated." The current estimate for a 4-mile-long rock tunnel subway is $275 million to $300 million.

Adams' letter also said, "No truncation of the route is contemplated as part of this analysis."

In a phone interview, Gleason said, "He can pick whatever paragraph he wants and say, 'That's what I said.' . . . They're paving the way to delete the line."

Gleason called Adams yesterday and asked him for a letter guaranteeing the construction of the Wheaton route. Adams refused.

Adams, also in a phone interview, said, "My feeling is that the future of the line is positive. But I can't put an absolute guarantee up front. We've got to work that line into the total bill" for Metro construction.

Sixty miles of the planned 100-mile Metro system are either funded or under construction. But the remainder is the subject of intensive study and not all of those miles are expected to survive that study.

The letter, Adams said, was an effort to "de-escalate this problem and try and get on to a solution."

Gleason has insisted, and Adamss has repeatedly denied, that certain staff members in the Department of Transportation are determined to torpedo the Wheaton line.