Mysore Nagaraja, president of the New York City subways’ first unit dedicated to its multibillion-dollar capital expansion program, is retiring in January. Nagaraja, a 23-year veteran of the Metropolitan Transportation Authority, has held the job since 2002. He says he will become a transportation construction consultant to city Deputy Mayor Daniel Doctoroff. Sources say Michael Horodiceanu, CEO of Manhattan-based consulting firm Urbitran, has been offered the job. He is a former city and state transportation official and associate of Metropolitan Transportation Authority chief Lee Sander.