This is the lower of the two spiral tunnels located between Lake Louise and Field. Here you see a CP train approaching the upper portal.
The next picture shows the train leaving the lower portal while the rear of the train is still approaching the upper portal.
What a way to get through the mountain barrier.
Robin

The next picture shows the train leaving the lower portal while the rear of the train is still approaching the upper portal.

What a way to get through the mountain barrier.
Robin