The bridge was built for an unknown location on the main line of the Baltimore and Ohio Railroad in 1852, and was moved to its present location, spanning the Little Patuxent River on the spur to the Savage Mill, in 1887.
This spur line dates to around 1840 and originally crossed the river on a stone arch bridge; however, due to alterations to the mill in the 1880s and topographical restrictions, a replacement bridge was needed.
The bridge remained in service until the mill closed in 1947; switching crews used additional cars in order to avoid crossing the bridge with locomotives, and thus there was never a need for a more substantial structure.
A smaller, narrower example was installed adjacent to the railbridge for road traffic, which was torn down after World War I.
It was the first successful all-metal bridge design to be adopted and consistently used on a railroad.
The design employs wrought iron tension members and cast iron compression members.
It was an improvement over wooden structures, as the independent structural units lessened the possibility of structural failure.
Patented on January 6, 1852, the company built about a hundred of these bridges through 1873.
Their durability and ease of assembly greatly facilitated expansion of American railroads in this period.
Bollman's Wills Creek Bridge has also survived, but it employs a different type of truss system.
The bridge was built for an unknown location on the main line of the Baltimore and Ohio Railroad in 1852, and was moved to its present location, spanning the Little Patuxent River on the spur to the Savage Mill, in 1887. This spur line dates to around 1840 and originally crossed the river on a stone arch bridge; however, due to alterations to the mill in the 1880s and topographical restrictions, a replacement bridge was needed. The bridge remained in service until the mill closed in 1947; switching crews used additional cars in order to avoid crossing the bridge with locomotives, and thus there was never a need for a more substantial structure. A smaller, narrower example was installed adjacent to the railbridge for road traffic, which was torn down after World War I.
It was the first successful all-metal bridge design to be adopted and consistently used on a railroad. The design employs wrought iron tension members and cast iron compression members. It was an improvement over wooden structures, as the independent structural units lessened the possibility of structural failure. Patented on January 6, 1852, the company built about a hundred of these bridges through 1873. Their durability and ease of assembly greatly facilitated expansion of American railroads in this period. Bollman's Wills Creek Bridge has also survived, but it employs a different type of truss system.
Bollman Truss Railroad Bridge