 Complete the following phrase:  The Baltimore and Potomac Railroad Station, also known as Pennsylvania Railroad Station, was a railroad station that was owned by the Pennsylvania Railroad and operated by the Baltimore and Potomac Railroad in Washington, D.C., from July 2, 1872 until its closure in 1907. It was located at the southern corner of 6th street NW and B Street NW now Constitution Avenue, now the site of the West Building of the National Gallery of Art. It was in this train station that United States President James A. Garfield was 