At 1340 hours on March 7, 1945, the main American attack began on Remagen. As the Americans fought their way to the western (or left) edge of the bridge, the Germans set off explosives, creating a 10-meter wide crater in the ramp of the bridge. At 1500 hours, the Americans paused, waiting for the bridge to be demolished by the Germans, but nothing happened. Unbeknownst to the Americans, the Germans had already tried to destroy the bridge several times, and under fire were struggling to repair the demolition wires to blow up the bridge. Finally, the Americans decided to take the bridge, and the order went out.
A large sign was placed on one of the stone towers marked "Cross the Rhine with dry feet courtesy of 9th Armd Division". The sign is now displayed at the Patton Museum of Cavalry and Armor at Fort Knox, Kentucky, above an M26 Pershing tank, a type used in the battle. During the days after the bridge capture, the U.S. 9th, 78th and 99th Infantry Divisions crossed the bridge. On March 17, 1945, despite furious Germans efforts to destroy it and Americans efforts to maintain it, the bridge collapsed. By then, Timmermann was on leave.
Timmermann was discharged from the Army on December 12, 1945. He became a salesman in Nebraska, raising his family. Timmermann missed Army life and tried to rejoin as an officer. However, all officer billets were full, so he enlisted as a technical sergeant in the Regular Army on October 28, 1947. He became a recruiter, and later an instructor with the Officers' Reserve Corps in Omaha, Nebraska.