Bollman truss bridge images

Wendel Bollman (1814-1884) from Baltimore started working for the B&O railroad and created a more stable bridge of iron for the trains. His first iron bridge was at Savage in 1850, and received a patent in 1852. Many photos (one of Mr. Bollman) and information at link below.

Covered turnpike bridge and trolley bridge at Ellicott Mills

A circa 1909 photograph shows the trolley bridge (on the left) and the covered bridge (for the road) crossing over the Patapsco to Baltimore County.