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| Name | CN 108th Avenue Bridge Duluth, Missabe & Iron Range Railway Bridge #SL10B |
| Built By | Spirit Lake Transfer Railway |
| Currently Owned By | Canadian National Railway |
| Superstructure Contractor | American Bridge Company of New York |
| Unknown | |
| Length | 265 Feet |
| Width | 1 Track |
| Height Above Ground | 15 Feet (Estimated) |
| Superstructure Design | Deck Plate Girder |
| Substructure Design | Steel Tower and Concrete |
| Date Built | 1913 |
| Traffic Count | 0 Trains/Day (Bridge is Closed to Traffic) |
| Current Status | Closed to all Traffic |
| Duluth, Missabe & Iron Range Railway Bridge Number | SL10B |
| Significance | Local Significance |
| Documentation Date | 2/8/2014 |
In 1907, the Spirit Lake Transfer Railway began construction on a new 14-mile route, extending from the St. Louis River bridge near Oliver, Wisconsin; to Adolph, Minnesota; near Duluth. At the same time, the Interstate Transfer Railway began construction on a new 11-mile route, extending from the St. Louis River Bridge to a junction with the Chicago & North Western Railway at South Itasca, Wisconsin. Work would be discontinued prior to completion of the route in 1913, and both railroads would be leased to the Duluth, Missabe & Northern Railway (DM&N) in 1915. Work would be resumed in 1915, and completed in 1916. This route served as a principal connecting line for the DM&N. The DM&N was owned by US Steel, and was operated with the purpose of facilitating iron ore shipments. The DM&N merged with the Duluth & Iron Range Railroad to form the Duluth, Missabe & Iron Range Railway (DM&IR) in 1938. US Steel continued to control the DM&IR until 1988, when the railroad holdings of that company were sold to Blackstone Group. The railroad was in turn sold to Canadian National Railway (CN) in 2003. This route continues to be operated as the CN Superior Subdivision.
Located near the Gary area of Duluth, this deck plate girder viaduct once carried the Canadian National Railway across 108th Avenue. Built in 1913 as the Spirit Lake Transfer Railway was building in this area, the bridge features a standard deck plate girder viaduct, consisting of five spans (two 70-foot, one 65-foot, two 30-foot). The bridge is set onto steel towers and concrete footings and abutments. The bridge also utilizes a sheet metal deck, typical for bridges in this area. This style of bridge was commonly used throughout this area, due to the rugged terrain and large waterways. Overall, the bridge appears to be in fair to poor condition, with some deterioration noted. The bridge was bypassed in 2016, when a new alignment opened to the south. The author has ranked this bridge as being locally significant, due to the common design.
Citations
| Builder and build date | American Bridge Company plaque |
| Railroad History Citation | ICC Valuation Information, Compiled by Richard S. Steele |