“Man,” I exclaimed. “That’s incredible.”

As a child, I recall my father parking at a lookout in Yoho National Park so that we could watch a freight train winding its way through the famous spiral tunnels. A true engineering marvel, the tunnels had been cut into the mountains allowing passage through seemingly impassable terrain. I remember watching a train disappear into a tunnel only to emerge a short time later at another place on the mountain and then disappear again. At one point, I could see the train in three different places at one time.

I could only imagine how dark and constricting the tunnels must have been for those building them. I imagined there were times when the workers saw only endless darkness. They blasted their way through the rock relying on skill, expe...

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