"There are four lines of plate girders, two under each track, of a uniform depth of 7'. Beginning on the east end there are two 75' plate-girder spans on a rocker bent; then six 45' plate girder spans, alternating with six 75' plate-girder spans. The 45' plate-girder spans carried on and form the tops of towers consisting of four columns each, rigidly braced together on all sides. The 75' plate-girders span the opening between consecutive towers.
"This bridge is one of the last projects of noted bridge engineer George Morison, who died two years after the structure was built. The bridge was the longest and heaviest viaduct of its time, and may be the longest extant double-track railroad viaduct in the world. It is listed in the National Register of Historic Places.
"This document was prepared as part of the Iowa Historic Bridges Recording Project performed during the Summer of 1995 by the Historic American Engineering Record (HAER). The project was sponsored by the Iowa Department of Transportation. (IDOT)."
Report of the Historic American Engineering Record
Nathan and Andy, next time you go visit the Kate Shelley Bridge, please take a drive down to the Des Moines River Wagon Bridge, a couple hundred yards downstream, and get some photos of the repaired structure. Thanks!
By the way, there is a well-written article from the June 2007 issue of the HDR, Inc. internal magazine. It talks about the old bridge, the new bridge, and the story of how Kate Shelley saved an express train in 1881, earning the grateful respect of the passengers on the express, praise from across the country and local residents, not to mention the Chicago & Northwestern. (Kate Shelley even took a job as a station master with the railroad, a position she held until her death in 1912.)
You can read it here: http://hdrinc.com/Assets/documents/Publications/RailLine/june2007/KateShelley.pdf
Here's a photo of Kate Shelley:
I went out today to see if I could see the new bridge in use, and what became of the old one. However, the new one is not yet finished. All the towers are done, but about 20% of the steel needs to be erected on the east end. So for now the old bridge is still in use.