When the Canadian Pacific Railway built their main line through the Rockies, they cheated a little bit on Kicking Horse Pass. Rather than take the time to build a tunnel, they built a "temporary" line with a 4.5% grade. The Big Hill stayed in use for 25 years, until a pair of spiral tunnels were built in Cathedral Mountain and Mount Ogden. The spiral tunnels are still in use today. This model of the tunnels was at the viewpoint along the Trans Canada Highway.
This is the real thing. We were lucky enough to be there when a train went through. Here you can see the middle of the train entering the tunnel down below while the locomotives pass above.
