The term METROLINER OPERATOR, ONCE is an acronym for the job title 'AMTRAK', which stands for the National Railroad Passenger Corporation. This is a government-owned corporation that provides intercity passenger train service in the United States. The METROLINER OPERATOR, ONCE was responsible for operating the Metroliner, a high-speed train service that operated between Washington, D.C. and New York City. The job required the operator to be knowledgeable about the operation of the Metroliner, as well as the safety regulations and procedures associated with it.