After wrestling with the issue for almost two years, the Architectural and Transportation Barriers Compliance Board yesterday approved minimum guidelines for making federal buildings accessible to the physically handicapped.

"This is the last chapter in a long saga," said William Bradford Reynolds, assistant attorney general for civil rights, who was elected chairman of the board at the meeting.

Handicapped groups successfully fought off attempts by four federal agencies to eliminate the guidelines and replace them with weaker standards.

The agencies--the Postal Service, the General Services Administration and the Defense and Housing and Urban Development departments--had developed uniform accessibility standards considerably weaker than the board's guidelines.

Their standards were to have been published in the Federal Register last week, but C. Boyden Gray, counsel for the Presidential Task Force on Regulatory Relief, asked the agencies to hold off until after yesterday's meeting.

Roger Craig, a Postal Service attorney, said that in light of the board's vote it was unclear whether the four agencies will go forward with their standards. Craig also said the board vote effectively killed his proposal, made last July, to abolish the guidelines.

None of the board's 21 members voted against the new minimum guidelines.

The latest version of the guidelines revises one issued in the closing days of the Carter administration. Besides making several technical changes, the board dropped all previous requirements for buildings that are leased by the federal government, citing a pending court case.

The board's former chairman, Mason Rose, a wheelchair-bound attorney, and two groups representing disabled veterans have sued the Postal Service, charging it has ignored existing laws in refusing to make its 15,000 leased post offices accessible to the handicapped. The Postal Service contends that the law does not cover leased facilities.

Congress created the barriers board in 1973 to draw up guidelines for agencies to use in adopting their own accessibility standards. Various agency officials have said that the earlier guidelines would be extremely costly.

Reynolds said that the new guidelines "do not impose on architects rigid requirements that are potentially terribly expensive."

Rose countered, however, that "the system that Congress conceived has broken down."

GSA and HUD made efforts at yesterday's meeting to relax several provisions, but those attempts were rebuffed.

The new guidelines stipulate that, in general, federal buildings under construction must have ramps, doorways, hallways and other facilities that can be used by the handicapped. When federal buildings are renovated, those same revisions must be made.

Among the more controversial provisions adopted was one requiring that, when additions are made, accessible entrances and toilet facilities must be provided somewhere in the building, even if the addition itself would not have an entrance or bathrooms. Board members from the GSA and Postal Service opposed that provision.