Omaha Railroad Bridge

View an article regarding the construction of this bridge.

Located between Council Bluffs, Iowa and Omaha, Nebraska; this iconic bridge carries the Union Pacific Railroad across the Missouri River. The first bridge at this location was built between 1869 and 1872, and featured 11 250-foot Post truss spans, set onto steel caisson substructures. The first bridge was fabricated by the American Bridge Company of Chicago, and was completed at a cost of approximately $2.9 Million Dollars. The Union Pacific charged tolls for freight and passengers using the bridge throughout the 1870s and 1880s, despite efforts to prevent tolls from being charged. By the early 1880s, the need for a new bridge had become evident. In addition, the Missouri River had shifted course, allowing for a shorter bridge to be constructed.

In 1885, George S. Morison was hired to design a new double track bridge to replace the Post truss bridge. It had been nearly two years since Morison had worked on a bridge, and he was reportedly enthusiastic to design a Missouri River bridge. Morison was joined by recent graduate Ralph Modjeski, a young engineer hired as the assistant to Morison. The two developed a strong working relationship, and Modjeski would continue to work with Morison until the mid-1890s. Modjeski later went on to design some of the most iconic bridges in the United States. Morison designed several more Missouri and Mississippi River bridges in his career.

Construction started on the new bridge in 1886, and would be completed in 1887. The new bridge would be substantially shorter, consisting of four 250-foot Whipple through trusses, set onto new stone piers. Similar to other bridges designed by Morison, the trusses of the bridge were constructed of steel, relatively early examples of steel railroad truss construction. These Whipple trusses were approached by three 125-foot 5-panel Pratt deck trusses on either end, set onto steel towers. New stone piers would be constructed by Saulpaugh & Company, and Union Bridge Company would fabricate the trusses. The new main span piers were staggered in the middle of spans of the Post truss. Three of the original steel caissons from 1869 were reused, one at each end of the first deck truss, and one for the east abutment. During the construction of the second bridge, trains were reportedly never interrupted for more than two hours, as the old truss spans were replaced with new spans. Two decorative statues were cast for the portals. The east portal utilized a bronze buffalo, while the west portal utilized a decorative shield displaying a plow, anchor and a steam hammer.

By 1916, the need for a new bridge had become evident. Prior to replacement, the old bridge was reportedly carrying 300 train movements per day. The need for train movements to be largely interrupted was paramount to the railroad. In response, two sets of timber piers would be constructed on either side of the existing bridge. The new bridge would be constructed on the downstream side, and hydraulic jacks installed to move the bridge into place. At 11 AM on December 23rd, 1916; the old bridge would be closed to traffic, and the replacement of the bridge would commence. By 12 PM, the old superstructure would be completely clear of the substructure, and by 4 PM, the new spans were installed and opened to traffic. The old spans were then disassembled, and reused at unknown locations as single track spans.

American Bridge Company was contracted to fabricate and erect the new bridge. The new bridge would utilize four 250-foot 8-panel pin connected Parker through trusses. A 120-foot 5-panel riveted Pratt through truss span would be installed on the east end, and two identical spans of 120 feet and 129 feet would be installed on the west side. Four deck plate girder spans would be installed on the east end, and two spans on the west end. New concrete and steel bent substructures would be constructed for the approaches. In addition, the original caisson piers at the ends of the first trusses would be reconstructed. A sheet metal encasement was wrapped around the bridge, and concrete poured to create solid piers. The east abutment was also modified with concrete, and the stone piers from the 1887 bridge would be reused. The main trusses utilize an M-frame portal, while the approach trusses utilize a more typical lattice portal. The main trusses utilize large built up members, while the approach span uses smaller members. The entire bridge utilizes a ballast deck design, typical of Union Pacific bridges.

Since the 1916 construction, the bridge has seen relatively few changes. In 2024, the bridge still serves heavy traffic, and is the main bridge across the Missouri River on the Union Pacific Overland Route, a railroad line extending from Chicago to California. Overall, the bridge appears to be well maintained and in good condition. It is believed that with proper maintenance, this bridge should continue to serve traffic for years to come. The author has ranked this bridge as being highly significant, due to the history of this crossing and the large scale truss design.