The selection of Scott Beardsley by the G.O.P.-appointed board comes after the previous president resigned under pressure from the Trump administration. A new Democratic-appointed board could try to overturn the choice.

Mayor-elect Zohran Mamdani said he did not know about the antisemitic posts and would not have hired the woman who made them if he had.

The bill, which would ensure that every train has a conductor and a driver, as most now do, was supported by the transit workers’ union and opposed by many transit advocates.