From Wikipedia: http://en.wikipedia.org/wiki/Tredegar_Iron_Works
By 1860, the Tredegar Iron Works was the largest of its kind in the South, a fact that played a significant role in the decision to relocate the capital of the Confederacy from Montgomery, Alabama to Richmond in May 1961.Tredegar supplied high-quality munitions to the South during the war. The company also manufactured railroad steam locomotives in the same period.
Tredegar Iron Works made the iron plating for the first Confederate ironclad warship, the CSS Virginia which fought in the historic Battle of Hampton Roads in March 1862. Tredegar is also credited with the production of approximately 1,100 artillery pieces during the war which was about half of the South's total domestic production of artillery between the war years of 1861-1865.
Tredegar also produced a giant rail-mounted siege cannon during the conflict. As the war continued with more and more men conscripted into the Confederate armies, Tredegar experienced a lack of skilled laborers. Scarce supplies of metal also hurt the company's manufacturing abilities during the war and as the conflict progressed it was noticed that Tredegar's products were beginning to lose quality as well as quantity. In the summer of 1861, after the beginning of the Civil War, the initial quantity of metal was so scarce that the iron works failed to produce a single piece of artillery for an entire month.
Model produced by drobbins of 3D Services. See it in Google Earth here.