Dean Jose Sert of the Graduate School of Design, and Serge I. Chermayeff, professor of Architecture, concerned by plans to completely rebuild Grand Central Terminal, have entered the fight to preserve the station's great concourse.

Their names, included among those of some 200 architects and designers, appeared on an open letter compiled by Architectural Forum from mail which had appeared in its columns.

The letter, which was sent to the New York Central, and New Haven Railroads which operate the Terminal, and reprinted in the Sunday Globe, called the concourse "one of those very few building achievements that have come to stand for our country."

Chermjayeff, who had written the magazine in protest, denied having given permission for the use of his name on the composite letter. "I consider the concourse to be an excellent example of 19th century Victorian madness and exuberant vulgarity," he said, "but it still performs a useful function."

"Every city requires a sheltered meeting place," Chermayeff continued, "and the great concourse is better than anywhere else. The fountain outside the Plaza Hotel is often cold and wet, and there just isn't enough room under the clock at the Baltimore."

Chermayeff, who said he like the concourse's spaciousness but disapproved of its architecture, is also worried about any possible replacement for it. "I suppose if they do tear it down," he said, "it will be replaced by some gargantuan monstrosity of black marble and chromium."