There is a misunderstanding as to determining which truss bridge type is a Whipple and which one is a Quadrangular Warren or even a Lattice truss bridge. Therefore before making the announcement about this bridge, one should look at the differences, beginning with the Warren Truss:
The simple Warren truss bridge was invented by James Warren in 1828 and features a truss span with alternating diagonal bracing, resembling the letter W. The Warren truss bridge can feature vertical posts but there are some that have either alternating vertical posts or none at all. Here are a couple examples to help you:
A double intersecting Warren truss features two Warren trusses that are reciprocal of each other, thus creating a rhombus-shaped Lattice design. An example of that bridge is featured here:
A Whipple truss bridge features diagonal beams that crosses two panels beginning at the top chord of the truss. For the end panels, two beams start at the top chord with one crossing one panel and the other two panels. An example of a Whipple truss bridge is here:
And finally the Quadrangular Warren truss features Lattice-like design where the diagonal beams cross each other four times. An example is here:
There is one truss bridge that stands out as the lone truss type of its kind in the world, and this bridge is the focus of our news story. The Chicago and Northwestern Railroad Viaduct, spanning the Chippewa River in Eau Claire, Wisconsin, is one of the main icons of the city of bridges (an article about the tour of Eau Claire is found here.) Built in 1880 by the Omaha Railroad, the railroad served traffic connecting Milwaukee and St.Paul, enroute to Sioux City and all points to the south and west. The bridge is 890 feet long with the longest span being 190 feet and the height is 85 feet, which can be seen by many people regardless of where they are situated (at the river side or up the hill). Approach spans were added by Lassig Bridge and Iron Works of Chicago in 1898. The bridge was in service until its abandonment in 2007. Yet by the beginning of 2013, the viaduct may have a new life as a pedestrian bridge.
Work has been underway to convert the bridge into a bike trail. connecting the business district on the west bank and the Dells Pond Area on the eastern side. It is expected that the viaduct will become part of the bike trail network by the beginning of 2013. What is so special about the viaduct is that it is the only Quintangular Warren Lattice bridge in the world. This means that diagonal beams cross each other five times, thus creating a Town Lattice design. To all memory, there is no other bridge in the world that has such a truss design.
Once the bridge is open to traffic, there will surely be talk about it being nominated for the National Register of Historic Places because of its bridge design and its connection with the history of Eau Claire and the Chicago and Northwestern Railroad, which bought the Omaha Railroad before folding into the Union Pacific Railroad conglomerate. It is unknown when and how it will be nominated, but it will be inevitable because of its unique design. It would also not be surprising if it receives the international recognition it deserves, joining the likes of the Bollmann Truss bridge in Maryland or even some of the bridges in Europe. But for now, the city, which owns the viaduct, is working hard to ensure that the bridge receives a new life as a bike and pedestrian bridge. This is something that the city of Eau Claire can take pride in alone.