7th Street Improvement Arches

Stone Arch Bridge over Bruce Vento Nature Trail
St. Paul, Ramsey County, Minnesota

Click the Photo Above to See All Photos of This Bridge!
Name 7th Street Improvement Arches
Built To Cross Northern Pacific Railroad
Chief Enginner William Albert Truesdell
Contractor McArthur Brothers of Chicago, Illinois
Currently Owned By Minnesota Department of Transportation
Length 90 Feet Total, 45 Foot Largest Span
Width (Underneath) 2 Tracks
Height Above Tracks 15 Feet (Estimated)
Superstructure Type Helicoidal Stone Arch
Substructure Type Stone Masonry
Date Built 1884
Traffic Count 0 Trains/Day (Bridge is a Trail)
Current Status Rails to Trails
Significance Regional Significance
In 1868, the Lake Superior & Mississippi Railroad Company planned to construct a line from St. Paul, Minnesota to Lake Superior in Duluth, Minnesota.
The first section, completed in 1868 was constructed from St. Paul to Wyoming, a city on the outskirts of the Twin Cities.
The second section was completed from Wyoming to 3 miles north of Hinckley by 1869, and the last section from Hinckley to Duluth in 1870.
The line became part of the St. Paul & Duluth Railroad in 1877, which became part of the Northern Pacific Railroad in 1900.
A new grade, which crossed through Thomson and Current Jay Cooke State Park was built in 1888 to avoid unfavorable grades around the Fon Du Lac Area.
Carlton, in Carlton County became a major interchange point for the NP, with its line towards Fargo, Superior, and its line towards Cloquet breaking off here.
The line continued to be operated by NP until 1970, when they merged with their rival, Great Northern Railway to form Burlington Northern.

Because Great Northern already had a parallel line, the BN decided to abandon parts of this line. The first chunk came in 1976 from New Duluth to Riverside Junction, a short distance of 4 miles.
A second blow came later that year, when the line was abandoned from Carlton towards Duluth. This section contained many twists and turns as it went through what would later be known as Jay Cooke State Park.
Continuing abandonments included from Hinckley to Moose Lake in 1977 and from Moose Lake to Carlton in 1980.
In 1989, the BN abandoned another segment from North Branch to Forest Lake, and from Hugo to Forest Lake in 1987.
Also in 1987, the southern section from the St. Paul Union Depot to White Bear Lake at I-694 was abandoned.
The remaining tracks came under BNSF Railway control due to a merger in 1996 between BN and Atchison, Topeka & Santa Fe Railway.

In 2019, there are two remaining sections. The southern one, currently owned by Minnesota Transfer Railroad runs from I-694 in White Bear Lake to the Washington County Line in Hugo.
The second segment is significantly longer and runs from North Branch to Hinckley, and is currently owned by the St. Croix Valley Railroad, which was created upon the sale of the tracks in 1997.
The entire line, known as the "Skally Line" is planned for trail development once the remaining tracks become available.
Currently, from North Branch to Hugo is the Sunrise Prairie Trail, while north of Hinckley is the Willard Munger State Trail. This section is 63 miles long, and the 5th longest paved trail in America.
In addition, a portion from I-694 to Saint Paul is now the Bruce Vento Nature Trail.

This bridge is a representative example of a grade separation project, where the railroad goes under the road.
Normally these types of structures would not be listed on this site. However, this structure has a high level of significance, and may have historically carried streetcars.
The bridge was built to serve as an improvement to 7th Street, which has to climb a massive hill out of Saint Paul.
The design chosen had to encompass the rail line below, as well as serve the traffic above. Construction would start 1883.
The design chosen was a two span stone arch (tunnel to the railroad). The arches were designed with a helicoidal design, meaning the stones are offset and skewed.
The Helicoidal design is exceptionally rare in the United States, and this is the only known one in Minnesota.
This was required because of the steel hill in which Seventh Street (MN-5) goes up. In addition, the structure was built with uneven sized arches.

Because of this design, this bridge is considered to be one of the most unique in the Twin Cities.

Today, the western arch carries the Bruce Vento Nature Trail, while the east is not in use.

The bridge is listed on both the National Register of Historic Places, as well as the American Historic Civil Engineering Landmarks. The bridge has been ranked as highly significant by the author, due to the design.
The photo above is an overview.


Source Type


Build Date Northern Pacific Bridge Book, provided by Northern Pacific Railway Historical Association
Railroad Line History Source ICC Valuation Information, Compiled by Richard S. Steele

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