Monocacy River bridge and viaduct

It was rebuilt by the Pennsylvania Railroad prior first in 1900-1905 as an open deck riveted iron plate under girder bridge.

In 1915, the bridge was surveyed as part of the Interstate Commerce Commission's ("ICC") effort to establish freight rates for the Parent railroad.

In 1927, the Pennsylvania Railroad rebuilt the bridge again using deeper and thicker steel girders, but leaving the masonry piers intact.

In 1900, Pennsylvania replaced the river trusses with a steel under girder, open deck bridge of four spans.

Later in 1927, Pennsylvania rebuilt the entire bridge using steel plate girders of half-inch thickness and measuring 85 inches in depth.