I want to know the answer to the following question:
With what airline does Amtrak codeshare for transit to Newark Airport that originates or terminates at Union Station?
All the background I'm provided with is that "Union Station is further served by four Amtrak lines: the Northeast Regional and the high-speed Acela Express provide service to New York, Washington, D.C. and Boston, and rank as the first and second busiest routes in the country; the New Haven–Springfield Line provides service to Hartford and Springfield, Massachusetts; and the Vermonter provides service to both Washington, D.C., and Vermont, 15 miles (24 km) from the Canadian border.". Is that enough to answer the question?
Answer: no