Lethbridge Viaduct

49.697469444444 - 112.8687Koordinaten: 49 ° 41 ' 50.9 "N, 112 ° 52' 7.3 " W

F1

Crowsnest Pass route of the Canadian Pacific Railway

Valley of the Oldman River

The Lethbridge Viaduct, also High Level Bridge, is a railway bridge near the city of Lethbridge in Alberta, Canada. Built as a scaffold pillars Viaduct ( Trestle construction) steel bridge spans the valley of the Oldman River. With a length of 1623.86 meters and a maximum height of 95.7 m, it is opened in the largest bridge of its kind Officially established by the Canadian Pacific Railway Lethbridge Viaduct in November 1909.

Location

The bridge is located in the south of the Canadian province of Alberta. It is part of the railway line through the Crowsnest Pass. The landscape in southern Alberta is indeed dominated by flat plains, however, rivers such as the Oldman River have dug into the plateau. The viaduct is located just west of the center of Lethbridge and entirely due to the municipality. On the east bank the bridge leads also about the "Indian Battle Park ," 1870 scene of a battle between Blackfoot and Cree.

Further west, crossing the railway line at Monarch Place a second time the Oldman River. This bridge is significantly shorter than the Lethbridge Viaduct with a length of 576 m.

Structure

The single-track bridge leads over 33 riveted, tapering towards the top steel lattice towers. When planning was paid to minimizing deformation by the often strong winds. Of the four cornerstones of each tower is anchored only ever a deep underground. The other three pillars can compensate for the temperature-induced change in length of the steel by graphite- lubricated slide bearings.

Each of the 33 bridge towers consists of two steel frames, which results in 67 bridge elements together with the two end panels. These are 44 plate girders, each 20.5 m in length, 22 plate girders, each 30.5 m in length and a 50.9 m long bottom chord truss. The installation of the truss was to bridge a steep slope on the west bank needed because there is no pillar was erected.

Unlike most Trestlebrücken the track does not pass the top of the structure, but as in the case of a trough bridge between the longitudinal beams, which are used as a railing. This is to prevent in case of a derailment that a car crash and you will damage one or more bridge piers. This proved to be already in the works, as a derailed carriage of a Bauzuges.

Planning and construction

The first railroad through the Crowsnest Pass was opened in 1898. The course was further south and crossed the St. Mary River and Belly River using low bridges in the river valley. This version made ​​20 wooden trestle bridges with a total length of 4.5 km is necessary, but the bridge over the St. Mary River was about 900 m long. In addition, the train operation was inhibited by gradients. In 1904 the wooden viaducts were in poor condition and was planned an alternative route between Lethbridge and Fort Macleod.

Work on the 132 concrete plinths of Lethbridge viaducts began in September, 1907, the foundations of the Oldman River were built using open caissons. Responsible for this work was the engineer John Edward Schwitzer, who also oversaw the construction of the Spiral Tunnels. The construction of the steel scaffolds began in August 1908. For this work, we constructed specially a large crane, abbreviated " traveler". It converted approximately 11,280 tons of steel have been installed, which anlieferte the train with 645 wagons from the work of the Canadian Bridge Company in Windsor. All in all required construction work about 900 truckloads of material. Until the summer of 1909 the work was completed. At the construction site about 100 men were employed, four workers were killed during construction. The costs amounted to C $ 1,334,525 against a quote from C $ 1,065,000 in 1905.

Even today, now over 100 years old Lethbridge Viaduct is traversed by heavy freight trains of the Canadian Pacific Railway.