 Under them he built numerous bridges, including the Green River Bridge in Kentucky, then the longest iron bridge in the nation, a bridge in Nashville, Tennessee over the Cumberland, and one over the Ohio at Louisville, Kentucky, which at one mile in length was the longest truss bridge of its time.During the Civil War he served in the road and machinery department as chief engineer and superintendent.Many bridges were destroyed and roads severed during this period, and Fink led the operating force to repair damages and guard against disasters.