Soo Line High Bridge

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Coordinates: 45 ° 7 '23 "  N , 92 ° 44' 39"  W.

Soo Line High Bridge
Soo Line High Bridge
use Railway bridge
Crossing of Saint Croix River
place Arcola, Minnesota and Somerset, Wisconsin
Entertained by Canadian National Railway
construction Truss - arch bridge
overall length 817 m
Longest span 107 m
Clear height 40 m ( HQ )
opening 1911
planner Claude Allen Porter Turner
location
Soo Line High Bridge (USA)
Soo Line High Bridge

The Soo Line High Bridge (also Arcola High Bridge ) is a single-track railway bridge over the Saint Croix River . The river crossing is on a 200-kilometer stretch of river that forms the border between the states of Wisconsin and Minnesota . It is located about two kilometers east of the small community of Arcola , Minnesota and five kilometers west of the city of Somerset , Wisconsin. The truss - arch bridge was built by Minneapolis, St. Paul and Sault Ste. Marie Railway (Soo Line)built and replaced a bridge on the Wisconsin Central Railway from 1884. The bridge is still part of a rail link between the Twin Cities and Chicago , which has been part of the Canadian National Railway network since 2001 after several mergers and acquisitions . In 1977, the 817 meter long and up to 55 meter high steel bridge was placed on the National Register of Historic Places under monument protection.

history

First railroad companies in Wisconsin in the late 19th century

Location of the Soo Line High Bridge Map pointer.svg in Wisconsin on the St. Croix River, right network of Wisconsin Central 1901
1901 Wisconsin Central map (Wisconsin highlighted) .jpg

The first railroad line in the still partly undeveloped and heavily forested northern half of Wisconsin was built in 1871-1877 by the Wisconsin Central Railroad from Neenah to Ashland . In the 1880s, the railroad expanded its network west to Saint Paul (1884) and south to Chicago (1886). In the 1890s, the Northern Pacific Railway (NP) leased the railroad network for 99 years, which allowed them to expand their northern transcontinental link between Puget Sound and Lake Superior to Chicago, completed in 1883 . In the second phase of the Great Depression from 1873-1896 , the NP had to give up the Wisconsin Central due to its own bankruptcy , which was finally reorganized in 1897 as the Wisconsin Central Railway . In 1908 the railroad company was transferred to Minneapolis, St. Paul and Sault Ste. Marie Railway (Soo Line) leased, which expanded the increasingly important east-west connection between Chicago and Saint Paul. This branched off from the original main route to Lake Superior at Abbotsford to the west and ran over Chippewa Falls to the Saint Croix River near Somerset . Here she crossed the river over a 25-year-old bridge, which could no longer cope with the increasing volume of traffic and the increased weights of the increasingly powerful steam locomotives . The Soo Line therefore decided on a new construction and a new route, which reduced the curve radii and gradients in the direction of Saint Paul to around 30 kilometers from New Richmond and the new bridge crossed the river one kilometer upstream from the old location.

Construction of the bridge through the Soo Line in 1910

At the site of the new bridge, the Saint Croix River forms a river bed over 500 meters wide, crossed by several river islands and bordered by steep sandstone slopes over 50 meters high . The commissioned bridge construction engineer Claude Allen Porter Turner therefore designed a single - track truss - arched bridge made of five three-hinged arches , which he added to the steep slopes with trestle bridges (scaffolding pillar viaducts) and which leads the track level at 55 m above normal water level. Construction of the foundations began in the summer of 1910. A temporary makeshift bridge and a material ropeway were used to transport the concrete . The steel superstructure manufactured by the American Bridge Company was built between October 1910 and June of the following year . This was carried out by the two banks, which after the completion of the first sheets with the other mostly in the cantilever could be continued. The first train passed the bridge on June 3, 1911. The old route continued for a few years and the old bridge was only demolished in 1916, the bridge piers from 1884 are still preserved.

Change of ownership from Canadian Pacific to Canadian National 2001

In 1961, the Canadian Pacific Railway reorganized several of its subsidiaries and merged Minneapolis, St. Paul and Sault Ste. Marie Railway with the Wisconsin Central Railroad and other railroad companies to form the Soo Line Railroad , which in turn sold much of the former Wisconsin Central lines , including the Soo Line High Bridge , to a consortium of investors in 1987 . These founded a company with the historical name Wisconsin Central , which was taken over in 2001 by the Canadian National Railway ; the Canadian Pacific acquired in 1990 all the remaining shares in the Soo Line Railroad , which has since than 100 - subsidiary is responsible for the US activities of the Canadian railway company -%.

In August 1977, the bridge was added to the National Register of Historic Places (NRHP # 77000056). The bridge, which is over 100 years old, was overhauled in 2016, with the concrete base of the steel arches and scaffolding pillars being repaired and new tracks being laid on the superstructure.

description

Schematic drawing of the Soo Line High Bridge from 1911 (left west, right east), given in the Anglo-American units feet (′) and inches (″)

The bridge, which extends in an east-west orientation, is divided into a central arched bridge made up of five 106.7 m long three - hinged arches , followed by trestle bridges 103.6 m long on the east side and 170.7 m on the west side . The track level is led at 55 m above normal water level on the top of the superstructure . The steel structure rests on concrete foundations that support the ends of the truss arches and the steel lattice masts of the Trestle bridges, each consisting of four individual concrete bases per arch or mast; The exception is the last steel pillar on the west side, which has only two bases. Since the middle bases each bear the supports of two adjacent arches, which are attached about 2.4 m apart, the total length of the steel construction is around 817 m between the abutments .

Truss arches

Schematic representation of the three-hinged arches with their five camps . There are swivel joints on the base and at the top of the arch ( lower chord ), and two slide bearings in the upper chord (under load, these block and a two-hinged arch is created )

In the steel construction of the arches, the lower chords form a three-hinged arch , the apex of which rises 38 m above the fighter line ( support on the concrete base). This is stiffened with the horizontally running upper chord through the framework to form a chipboard groove . The top chord consists of 1.5 m high solid wall girders , the construction height is 47 m on the outside and 7.6 m at the apex. The center lines of the upper chords are 2.7 m apart, those of the lower chords 18 m at the height of the supports. The lower chords are rotatably mounted at their ends and at the apex with bolt connections , creating a three-hinged arch. Horizontal slide bearings are integrated into the middle element of the upper chords , which allow temperature-related movements under the weight of the steel structure. Under load from train traffic, these block and a two-hinged arch is created . The foundations of the arches consist of 13 m high pyramid-shaped concrete bases with areas of up to 11 m × 10 m, which protrude about 4 m from the ground or above low water. The middle bases, each supporting two arches, are anchored in the ground by means of pile foundations , with 110 piles being driven up to 24 m into the ground per base, which protrude 1.5 m into the foundations.

A freight train crossing the bridge in March 2009

Trestle bridges

The steel trestle bridges of the access roads consist of 2.7 m high solid wall girders, which, like the top chords of the arches, rest on several steel masts of different heights at a distance of 2.7 m. The length of the girders varies from 12 m on the masts to 30 m between them. The height of the steel lattice masts decreases towards the edges of the valley from 37 m to 11 m, whereby the difference is more pronounced on the east side and the concrete bases are sometimes at different heights. All bases of the masts, like the outer foundations of the arches, stand directly on the sandstone subsoil of the valley edges.

literature

Web links

Commons : Soo Line High Bridge  - collection of pictures, videos and audio files

Individual evidence

  1. ^ Wisconsin Central Railway. American-Rails.com, accessed May 4, 2020.
  2. ^ Henry Varnum Poor: Poor's Manual of Railroads. Vol. 24, New York 1891, p. 403.
  3. ^ Henry Varnum Poor: Poor's Manual of Railroads. Vol. 40, New York 1907, pp. 607-611.
  4. ^ Henry Varnum Poor: Poor's Manual of Railroads. Vol. 43, New York 1910, pp. 924 f.
  5. ^ Railway Projects: Minnesota, St. Croix and Wisconsin. In: Railway World. Vol. 28, July 12, 1884, p. 662.
  6. ↑ a b c Pierce P. Furber: The Steel Arche Bridge Over the St. Croix River. In: Engineering & Contracting. Vol. 36, No. 23, 1911, pp. 609-611.
  7. ^ WC - St. Croix River High Bridge (1884-1916). BridgeHunter.com, accessed May 4, 2020.
  8. ^ A b C. AP Turner: The St. Croix River Bridge. In: Transactions of the American Society of Civil Engineers. Vol. 75, December 1912, pp. 1-11.
  9. ^ The Wisconsin Central Story. ( Memento of March 24, 2006 in the Internet Archive ) Canadian National Railway Company, 2006.
  10. ^ Soo Line High Bridge. NPGallery Digital Asset Management System, National Park Service. Retrieved August 20, 2019.
  11. ^ Greg Seitz: Railroad Company Plans to Restore High Bridge Footings. St. Croix 360, May 31, 2016, accessed May 4, 2020.
  12. ↑ 2016 Arcola High Bridge Rail Replacement. YouTube video, August 17, 2016, accessed May 4, 2020.
  13. ^ A b c d Soo Line Cut-Off from New Richmond to Withrow. In: Railway Age Gazette. Vol. 51, No. 22, 1911, pp. 1091-1095.
This article was added to the list of articles worth reading on May 16, 2020 in this version .