For the week of June 22, 2026.
On June 22, 1909, builders in Alberta laid the final span of the Lethbridge Viaduct, the longest and highest railway bridge in Canada. Engineers developed innovative techniques to build this bridge of unprecedented scale across the windy Oldman River Valley in the ancestral territory of the Nitsitapii (Blackfoot). The viaduct still stands as a landmark of engineering and advanced railway design.
In the late 19th century, coal fields drew mining and railway interests to Southern Alberta. Lethbridge became an important transportation hub, with connections to Medicine Hat, Calgary, the United States, and British Columbia’s Kootenay Valley. Along the line that crossed the nearby Oldman River Valley, trains had to make 37 sharp curves and go over 20 wooden bridges. Many trains derailed on the turns and the bridges quickly fell into disrepair. The Canadian Pacific Railway conducted surveys and concluded a high-level steel viaduct was needed so trains could safely travel across the valley at higher speeds while carrying heavier loads. In 1907 construction began on the span bridge, which straightened the track, reduced its steepness, and shortened the travel time between Lethbridge and Macleod (Fort Macleod after 1952).
The Assistant Chief Engineer of the Canadian Pacific bridge department, John Edward Schwitzer, designed the substructure of the impressive bridge and directed its construction. Engineer of Bridges Charles N. Monsarrat created the original bridge design. The first step in the process was excavation work for the concrete piers that would support the bridge. Steelwork began in August 1908. The viaduct consisted of 33 towers supporting 66 plate girder spans running between them. The spans ranged between 20 metres and 30 metres in length, for a bridge that rose 96 metres high and spanned 1.6 kilometres across the valley.
The severe winds of the valley presented a unique challenge to construction. When building span bridges, crews used machines called travelers that glide along constructed sections and allow workers standing on overhanging platforms to install the next span. To keep workers safe in the windy conditions at Lethbridge, construction engineers added a suspended cage to the traveller to prevent people from being blown off the viaduct. Despite these measures, two men fell from bridge towers during construction, and one died. Two other crew members died while rescuing a child who got stuck in an excavation pit filled with noxious gas from a buried coal mine.
The high winds also influenced the bridge design. The railway track itself was inset between the steel spans, rather than running on top of them, to prevent derailed cars from being swept off the bridge. The support towers were attached to the concrete piers with one fixed corner and three tongue-and-groove corners that could move slightly with the wind or expansion of the steel.
These innovations meant that a crew of about 100 men completed the extensive steelwork in under a year, with the final span lifted into place on June 22, 1909. That afternoon, the crew ferried 100 Lethbridge citizens across the bridge on flatcars to step foot on the other side. Today, the viaduct is still an active rail bridge, with both freight and passenger trains regularly crossing the Lethbridge landmark.
