Digging into the archives from a few years back, we find some photos showing a massive railway bridge located on the CPR’s busy east/west mainline in the former town of Mitford, very near Cochrane. This structure is old and in times now gone, it once saw the passing of many steam trains. Now it supports, without any trouble, a huge number of heavy freights that travel over the structure every single day.
This a Pratt Truss design bridge, a form very common in railway circles. Most date from some time ago – they were very popular with new construction in the first couple decades of the twentieth century. Given that railway bridges are made to last, many remain in use long after they were built.
In this style the diagonals slope from top to bottom towards the centre of the structure. Many Pratt bridges support roads too. They can span moderate length crossings and can be used singly, or two or more spans can be interconnected using intermediate piers.
Pratt bridges can be through style – meaning there are cross-connected girders tying the the two sides together at the top of the truss. Or they can be pony style, ie open topped. Railway bridges made in the Pratt form are almost exclusively through types.
I’s not known when the bridge was built. We looked on the structure itself for a date plate and found none. Later we contacted many sources who may or could know about it, all without success. No one wanted to talk with us! However, given the style, which recall we said was common for new or replacement bridge builds for many railways, including the the CPR, in the 1900-1920 period, it’s safe to assume this structure is also from around that time.
Given its advanced age, the bridge has no problem supporting the bigger, longer, heavier trains of today. As with everything, infrastructure wise that the CPR constructed, it was over-built to a great degree and there is no reason to believe it’ll continue to support trains for many decades to come.
This is not the first railway bridge at this spot. Earlier there was a wood-framed structure here, dating from back when the track came though the area.
In the one picture you’ll notice an extra set of rails, parallel too and located inside the running rails, on the track structure itself. These are check (or guard) rails which simply keep a derailed car, heaven forbid that should happen, from damaging the structure. They force the car’s wheels to stay in line with the main track and the car upright, thereby mitigating the potential for damage – better to wreck some cross ties then steel work. These are commonly seen on bridges, in tunnels and in other close clearance areas where a car coming off the tracks could cause serious problems.
The railway line here is the CPR’s Laggan Subdivision, that firm’s Trans-Canada mainline, and dates from the 1880s. Many trains pass this spot every day. In fact, in the time we took to explore the place, which took an hour or so, five zipped by. We photographed a couple, including one super-train with so many locomotives (DPUs or distributed power units in railway nomenclature), that we lost count.
At one time there used to be a road bridge just to the south of the train bridge. Maps from the 1890s make mention it was privately owned and a toll had to be paid to cross it. We looked for evidence of this old structure but found nothing. It was made of wood, so that’s not surprising I guess.
The location of this bridge is officially at the ghost town of Mitford, founded in the 1880s and abandoned by the turn of the twentieth century. The empty field to the north of the bridge, only metres away, is where it once stood. All that’s left is the cemetery. The bedroom community of Cochrane is encroaching on this site very quickly.
The Bow River, which the CPR’s Cochrane/Mitford bridge crosses, originates in the mountains to the west before passing though here, and later Calgary, before continuing its journey east. It flooded badly in the spring of 2013, but from what I’ve heard the bridge sustained no real damage. Like I said, the CPR built things to last.
If you wish more information on what you’ve seen here, by all means contact us!
Date: September, 2012.
Location: Mitford, AB.
Some places we’ve shown are on private property and care should be taken when exploring them.