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| Name | Robert Street Lift Bridge Chicago Great Western Bridge #424.50 |
| Built By | Chicago Great Western Railway |
| Currently Owned By | Union Pacific Railroad |
| Superstructure Contractor | American Bridge Company of New York Bethlehem Steel Company of Bethlehem, Pennsylvania (North Approach) |
| Substructure Contractors | Widell Company of Mankato, Minnesota Unknown (North Approach) |
| Erection Contractors | Unknown |
| Engineer | Waddell & Harrington of Kansas City, Missouri |
| Length | 960 Feet Total, 192 Foot Lift Span |
| Width | 1 Track |
| Height Above Ground | 15 Feet (Estimated) |
| Superstructure Design | Pratt Through Truss, Deck Plate Girder and Steel Stringer |
| Substructure Design | Concrete and Steel Bent |
| Date Built | 1912, Raised 1926; North Approach Added 1955 |
| Traffic Count | 5 Trains/Day (Estimated) |
| Current Status | In Use |
| Great Northern Railway Bridge Number | 424.50 |
| Union Pacific Railroad Bridge Number | 529.52 |
| Significance | High Significance |
| Documentation Date | 6/3/2012; 12/27/2017; 5/27/2023 |
In 1885, the Minnesota and Northwestern Railway (M&NW) built 129 miles of railroad between St. Paul, Minnesota and Manly, Iowa; running through towns such as Austin, Minnesota. By 1887, the M&NW would be merged with the Chicago, St. Paul and Kansas City Railway Company, which would in turn be purchased by the Chicago Great Western Railway (CGW) in 1893. In 1901, 9 additional miles would be constructed between Manly and Mason City, Iowa by the Mason City & Fort Dodge Railway (MC&FD). The MC&FD would be leased by the CGW the same year. In 1902, the CGW would sell the Hayfield-Manly segment to the leased MC&FD.
In 1909, the CGW would be reorganized as the Chicago Great Western Railroad (CGW). The CGW and leased MC&FD operated the route until 1968, when the CGW was purchased by the Chicago & North Western Railway. The route was unprofitable by the 1970s, and the Hayfield to Austin segment was abandoned in 1977. Further abandonment came in 1981, when the Manly to Austin segment was abandoned, in 1982 when the Randolph to Hayfield segment was abandoned, and in 1984 when the Roseport to Randolph segment was abandoned.
In 1995, the C&NW was purchased by the Union Pacific Railroad, which continues to operate two of the segments in 2023. The Mason City to Manly segment is operated as part of the Albert Lea Subdivision, and the St. Paul to Roseport segment as the Roseport Industrial Lead. The remainder of the route is abandoned, with many sections completely removed without a trace.
Likely the most iconic railroad bridge in St. Paul, this large lift bridge crosses the Mississippi River at an angle below Robert Street. The previous bridge here was built in 1885, and consisted of Whipple through trusses and a swing span. In 1912, it was desired to replace the bridge with a heavier structure. In response, a 192-foot vertical lift span would be constructed, with a deck plate girder approach. The main span of the bridge is a 192-foot riveted Pratt through truss span, with A-frame portal bracings, laced members and 7 panels. The lift span is supported by two large steel towers, which utilize concrete blocks for counterweights to raise and lower the span. The bridge was originally approached by seven 79-foot deck plate girder spans on the south side, and one 79-foot deck plate girder span on the north side. The bridge originally was set onto concrete substructures. The lift span was designed by Waddell & Harrington of Kansas City, Missouri; and the bridge was fabricated by American Bridge Company.
When the new St. Paul Union Depot was constructed, it was necessary to raise the grade of this bridge. The profile grade of the bridge was changed from -0.80% to +0.80% by adding steel bent risers on the existing concrete piers. Further changes were made to the bridge in 1955, when two steel stringer spans on concrete substructures were added on the north end of the bridge to cross Warner Drive. Since the initial construction, the lift span of the bridge has been strengthened, with new bolts and plates. This style of bridge was preferred by railroads for navigable rivers, as it provided a clearance without the need for a center pier.
As of January 2024, plans are underway to replace the lift span of this bridge with a new bascule span. The current lift span is in poor condition, and has become a maintenance issue for the railroad. It is currently unknown when this work will be completed, but a Section 106 evaluation is underway as of September 2021. Overall, the bridge appears to be in fair to poor condition. While the approach spans appear to be in acceptable condition, the lift span is in poor condition, with significant section loss and deterioration throughout the towers and span. The author has ranked this bridge as being highly significant, due to it being one of only a handful of vertical lift spans in Minnesota.
Citations
| Builder and build date | American Bridge Company plaque |
| Builder (Approach) | Bethlehem Steel Company plaque |
| Builder (Substructure) | Engineering Record, Building Record and Sanitary Engineer, Volume 68 |
| Railroad History Citation | ICC Valuation Information, Compiled by Richard S. Steele |