Monday, August 23, 2010

Of Spiral Tunnels and More Things Bow

We started our last day in Banff by making a wrong choice of roads (Trans Canadian Highway 1 instead of the Icefields Parkway) and going into Yoho National Park in British Columbia.  There we discovered a viewpoint devoted to the building of the Canadian Pacific's transcontinental line through the Rockies.  The line came from Calgary to Banff, then to Lake Louise, and then through Kicking Horse Pass into B.C.  The steep drop on the west side of the pass created challenges for the railroad.  Starting in 1885 until 1910, the line had an unsafe 4.5% grade, extreme since the Canadian standards even then set a 2.5% grade as the maximum safe one.

To get around the difficulty, the CPR engineers decided to adopt a Swiss idea - that of a spiral tunnel.  They tunneled two spirals into the face of the mountain, allowing for a safe grade.

We were at the viewpoint labeled "You are Here" and watched an eastbound freight train enter the lower tunnel at Point 1 and emerge at Point 2.
Freight Cars Entering the Lower Spiral
Freight Train Emerging from the Lower Spiral Tunnel
Come to think of it, it's remarkable to note that these spiral tunnels have been in use for 100 years.

We got ourselves pointed in the right direction, went back to the Icefields Parkway (Route 93, and turned north to Bow Lake.  The Bow River has its origin with the Bow Glacier, maybe 25 miles north of Lake Louise,  The melt from the glacier tumbles down Bow Glacier Falls and out across a braided river (delta) into Bow Lake, which in turn drains into the Bow River.  (Just to the north of the lake is Bow Summit, which divides the Bow River watershed from those that flow toward the north.)
Bow Lake with Bow Glacier in the Background
We had a snack at a funky lodge on the lake.  The lodge intrigued me as the only one we'd been in that seemed to be part of the land, built to fit in the relative isolation of its setting.
Then we went out the trail toward Bow Glacier Falls, a relatively easy trail with its elevation gain concentrated on the last few hundred meters.
From Falls to River