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| Name | CN Topper Drive Bridge Illinois Central Railroad Bridge #D-168.52 |
| Built By | Illinois Central Railroad |
| Currently Owned By | Canadian National Railway |
| Superstructure Contractor | Unknown |
| Substructure Contractor | Unknown |
| Length | 48 Feet Total |
| Width | 2 Tracks |
| Height Above Ground | 13 Feet 11 Inches |
| Superstructure Design | Through Plate Girder |
| Substructure Design | Concrete |
| Date Built | 1940 |
| Traffic Count | 10 Trains/Day (Estimated) |
| Current Status | In Use |
| Illinois Central Railroad Bridge Number | D-168.52 |
| Canadian National Railway Bridge Number | 168.52 |
| Significance | Local Significance |
| Documentation Date | 2/17/2024 |
In 1871, the Gilman, Clinton & Springfield Railroad (GC&S) completed 102 miles of new railroad, extending from the Illinois Central Railroad (IC) mainline at Gilman, Illinois to Springfield, Illinois. This route provided an underserved area in Central Illinois with a reliable railroad connection. In 1873, the GC&S would become bankrupt, and in 1877 would be acquired by IC subsidiary Chicago & Springfield Railroad (C&S). The C&S was formally consolidated into the IC in 1902, and IC significantly improved the track between Gilman and Springfield, constructing new bridges and realigning the railroad. Further improvements would be made in 1923, when a segment near Springfield would be double tracked. By the 20th Century, the IC was a respected railroad, operating an extensive railroad network through the central United States. Throughout the later part of the 20th Century, traffic on this line began to fall, and the line became more of a connecting line for the railroad. In 1972, the IC merged with the Gulf, Mobile & Ohio Railroad (GM&O) to form the Illinois Central Gulf (ICG). In 1988, the ICG was reorganized as the Illinois Central Railroad (IC). In 1998, IC was purchased by the Canadian National Railway (CN). Today, CN continues to operate this line as the Gilman Subdivision.
Located on the northeast side of Mt. Pulaski, this through plate girder bridge carries the former Illinois Central Railroad over Illinois Route 121 (Topper Drive). In the 1920s and 1930s, the Illinois Department of Public Works and Buildings (now Illinois Department of Transportation) partnered with railroads throughout the state to construct grade separations at high traffic crossings and improve roadways throughout the state. In the late 1930s, Illinois Route 121 would be realigned around Mt. Pulaski, and a new underpass constructed at the Illinois Central Railroad. Work on the project began in 1938, and the underpass opened in 1940. The bridge consists of a 40-foot double track through plate girder span, set onto concrete abutments. The girders use a concrete floor, which creates a ballast deck. In addition, the bridge is set at a heavy skew. Concrete floors like the one on this bridge were popular with some railroads, and provided a greater level of protection to steel components of the superstructure. Typical of grade separations from this era, the bridge uses some decorative features, including stepped wing walls. Since the initial construction, the bridge has seen little alterations. Overall, the bridge appears to be in fair to good condition, with no significant deterioration noted. The author has ranked this bridge as being locally significant, due to the common design.
Citations
| Build date | Illinois Central Gulf Illinois Division 1978 Track Profile |
| Railroad History Citation | ICC Valuation Information, Compiled by Richard S. Steele |