The parties yesterday missed a seven-day deadline set by the M.T.A. at its board meeting last week, with the final details of a conditional letter of designation yet to be finalized. That came after the parties missed a self-imposed deadline of two weeks from the initial announcement.

At the board meeting last week, the M.T.A. said Tishman put an initial signing fee of $11 million into escrow as the parties neared an agreement, though issues over infrastructure costs remained unsolved.