Railway guns like the German WWII K5 gun had a very narrow aim. To get around that problem, Germans developed a circular track, allowing the gun to rotate and fire in 360 degrees.

A K5(E) is preserved at the United States Army Ordnance Museum in Fort Lee (Petersburg, Virginia). Leopold was shipped to the U.S. Aberdeen Proving Ground, (Aberdeen, Maryland) where it underwent tests and evaluations. In early 2011 it was moved to Fort Lee, Virginia (37.250338°N 77.340492°W) as a result of the 2005 Base Relocation and Closure (BRAC) Act.

The guns were discovered on a railroad siding in the town of Civitavecchia, on 7 June 1944, shortly after the allies occupied Rome.[2] Robert had been partially destroyed by the gun crew before they surrendered and Leopold was also damaged but not as badly.