Quincy Railroad Bridge

View an article discussing the 1960 construction of this bridge

View an article discussing the 1898 construction of the previous bridge

Since the early 1850s, Quincy had been an important railroad town, located along the Mississippi River. The Chicago, Burlington & Quincy Railroad (CB&Q) operated a line into Quincy; and across the Mississippi River, the Hannibal & St. Joseph Railroad operated a line to Kansas City, Missouri. During the 1860s, the two railroads desired to construct a bridge across the Mississippi River, connecting the two systems. In 1866, the crossing was approved by the United States Congress, and the Quincy Bridge Company was incorporated to oversee the work. The crossing would be comprised of two main structures, including a large bridge across the main channel, and a smaller structure across Quincy Bay. The bridges were designed by Thomas C. Clarke, and fabricated by the Detroit Bridge & Iron Works. The railroad company provided the labor for construction of the substructures. Both structures would utilize swing spans to accommodate riverboat traffic, and were completed in 1868. The two bridges were initially connected by a wooden trestle, which was filled during the early years of the structure.

The first Quincy Bridge consisted of seventeen truss spans, set onto stone substructures. From the Illinois side, the bridge consisted of a 200-foot Whipple through truss, followed by eleven 157-foot spans, two 200-foot spans and one 250-foot span of the same design. The swing span of the bridge consisted of a 362-foot span, with clear openings of 160 feet. This span was located near the west bank of the Mississippi River. The westernmost span of the bridge was a 250-foot Whipple through truss span. The bridge was constructed using Phoenix Columns, and utilized a light portal with solid heel bracing. The stone substructures of the bridge were constructed of dolomite stone quarried at Keokuk, Iowa and Grafton, Illinois.

By the 1890s, the 1868 structure had become inadequate for traffic, and would need to be replaced. Beginning in 1897, Union Bridge Company replaced the bridge, reusing the stone piers. During the reconstruction, the bridge was shortened by seven spans to accommodate a new line to serve terminals along the river in Quincy. In addition, a wagon deck was added to the outside of the bridge. The nine fixed spans were replaced between 1897 and 1898. The eastern spans of the bridge would consist of five 157-foot, 7-panel, pin-connected Pratt through truss spans, followed by two 200-foot, 7-panel spans; a 250-foot, 11-panel span and another 250-foot span of the same design on the west end. A 52-foot deck plate girder span was also constructed on the east end. These spans utilized a standard CB&Q design, including laced members and a standard CB&Q portal. The 200-foot and 250-foot spans used an X-frame portal bracing, likely due to the larger length of the structure. The 250-foot spans were exceptionally long for Pratt spans. The original swing span, which had been strengthened in the 1890s, was replaced in 1901. Upon replacement of the 1868 bridge, the truss spans were reused throughout the CB&Q system, particularly on branch lines and for viaducts. It is currently unknown if any of these spans survive today.

After the opening of the Quincy Memorial Bridge in 1930, the roadway deck on the bridge was closed. In 1948, the pier of the swing bridge was struck by a barge, closing the structure to traffic for three months. During the 1950s, the CB&Q and the Army Corp of Engineers debated replacing the bridge, which was considered a navigation hazard. The Corps ultimately issued an order that the navigation channel be moved 1,400 feet east, which would require an extensive reconstruction of the bridge. Instead of reconstructing the aging bridge, the CB&Q decided to construct a new bridge, approximately 500 feet upstream. In addition, the new alignment would be significantly higher than the old line. Construction on the new bridge and alignment was began in 1959, and completed in 1960. After completion of the new line, the old bridge would be removed and scrapped almost immediately.

The current bridge consists of a large 336-foot, 12-panel polygonal Warren through truss span, approached by seven 228-foot, 10-panel riveted Warren deck trusses. The west end of the bridge is approached by four 84-foot deck plate girder spans, and the east end is approached by two 95-foot deck plate girder spans. The entire structure is set onto concrete substructures. The bridge was constructed by floating assembled spans into position. The truss spans utilize design features typical of bridges from the era, including solid members and heavy riveted connections. In addition, the bridge was an early structure to use high strength bolts, which were used to connect segments of the structure. Overall, the bridge appears to be in fair condition, with no significant deterioration noted. The author has ranked the bridge as being moderately significant, due to the truss design.