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| Name | CSX I&M Canal Bridge |
| Built By | Chicago, Rock Island & Pacific Railway |
| Currently Owned By | CSX Corporation |
| Superstructure Contractor | American Bridge Company of New York |
| Substructure Contractor | Unknown |
| Length | 140 Feet Total |
| Width | 1 Track |
| Height Above Ground | 5 Feet (Estimated) |
| Superstructure Design | Deck Plate Girder |
| Substructure Design | Concrete |
| Date Built | 1911 |
| Traffic Count | 1 Train/Day (Estimated) |
| Current Status | In Use |
| Significance | Moderate Significance |
| Documentation Date | 12/16/2018 |
In 1852, the Chicago and Rock Island Rail Road Company (C&RI) constructed 40 miles of new railroad, extending from Chicago, Illinois to Joliet, Illinois. The following year, the railroad constructed an additional 119 miles of new railroad to Geneseo, followed by an additional 22 miles to Rock Island, Illinois in 1854. Work was continued in 1856 by the Mississippi and Missouri Rail Road Company (M&M), which constructed a bridge across the Mississippi River to Davenport, Iowa and continued the line westwards across Iowa. In 1866, the two railroads were consolidated into the Chicago, Rock Island & Pacific Railroad, which was renamed the Chicago, Rock Island & Pacific Railway (Rock Island) in 1880. The line between Chicago and Joliet was double tracked prior to 1874, due to the heavy use. The Rock Island constructed and acquired a large network of railroads, primarily in Iowa during the late 1880s. This line served as a principal mainline for the railroad, connecting Chicago to the network of railroad lines west of the Mississippi River.
In approximately 1892, the remainder of the line would be double tracked, and in the late 1890s, additional tracks were added in Chicago. Track elevation projects within Chicago were made throughout the late 1890s and early 1900s. Throughout the 20th Century, the line continued to be a critical component of the Rock Island system. In 1913, the Rock Island elevated the line through Joliet. The Rock Island was a poor railroad, facing financial trouble regularly and often in bankruptcy. This route hosted passenger trains known as "Rockets" for many years, and the Rock Island offered a suburban commuter service over the line. After World War II, the Rock Island struggled to survive, proposing mergers and deferring maintenance on their routes. By 1964, the Rock Island began attempts to merge with Union Pacific, and restructure railroads west of the Mississippi River. This merger was eventually denied, and Rock Island turned its last profit in 1965.
In the mid-1970s, the
railroad was in serious decline. The railroad received loans to attempt
to fix slow orders, received new equipment and turn a profit. By 1978,
the railroad came close to profit, but creditors were lobbying for a
complete shutdown of the Rock Island. During the fall of 1979, a strike
crippled the railroad, and by January of 1980, the entire system was
ordered to be shut down and liquidated. Many of the lines and equipment
were scrapped. Profitable sections of railroad were prepared for
sale. Between Joliet and Chicago, the line would be sold to the Regional Transportation Authority. From Joliet to Utica, the line would be sold to the Chessie System, which became part of CSX Transportation in 1986. The portion from Utica into Iowa would be sold to the Iowa Interstate Railroad (IAIS). Today, the Chicago to Joliet segment is operated by Metra as the Rock Island District; CSX operates the line between Joliet and Utica as the New Rock Subdivision; and IAIS operates the Rock Island to Utica section as the Blue Island Subdivision.
Located in Rockdale, this deck plate girder swing bridge carries a spur of the former Chicago, Rock Island & Pacific Railway over the Illinois & Michigan Canal. During the late 19th and early 20th Centuries, a number of spurs were constructed across the Illinois & Michigan Canal to connect to industries located along the Illinois River. It is unknown if there was a previous structure at this location. Built in 1911, the bridge consists of a 140-foot deck plate girder swing span, set onto concrete substructures. The swing span is symmetrical, and girder span is continuous, using tapered ends which allow clearance for rollers at the abutments. The girders are heavily constructed, with the bottom of the steel only a couple of feet above the water. The span appears to be center bearing, with the center set directly onto the pier. Typical of swing spans, the center pier is round and covered by a gear. American Bridge Company fabricated the superstructure, and it is unknown if the substructures were constructed by railroad forces or by an unknown contractor.
While a number of girder swing spans once crossed the Illinois & Michigan Canal, only two remain today. Girder spans were occasionally used for railroad swing spans, as they were durable and easier to construct than trusses. However, these types of bridges were largely limited by span length, due to the nature of the girder design. Since the 1911 construction, the bridge has possibly seen some alterations. Currently, the girders are set directly onto a gear on the center pier. Typically, swing spans were set onto rollers. Due to the limited clearance and water underneath the structure, it is unknown if there are rollers that are hidden from view. It is possible that the bridge did not originally use rollers, and that it instead turns by a gear system which is directly affixed to the center pier. It also is possible that the original rollers were removed, rendering the bridge inoperable. Currently, the bridge is used sparingly, and the spur is abandoned immediately south of the bridge. Overall, the bridge appears to be in fair condition, with spalling noted throughout the substructures. The author has ranked this bridge as being moderately significant, due to the swing span design.
Citations
| Builder and build date | American Bridge Company plaque |
| Railroad History Citation | ICC Valuation Information, Compiled by Richard S. Steele |