Underwood also designed stations for the Union Pacific, culminating in the magnificent Art Deco style station in Omaha in 1931. Then Underwood joined the Federal Architects Project in 1932. While working for the federal government, Underwood produced the preliminary designs for the Timberline Lodge, Mount Hood, Oregon, and went on to design more than 20 post offices, two major federal buildings, and the U.S. State Department Building. From 1947 to 1949, he was appointed as federal supervisory architect.
