If you’re a train nut and in the Banff area then you might want to make a stop at the Kicking Horse Pass near the town of Field on Hwy-1 (Trans Canada Hwy). The viewpoint contains a large parking lot, informational signs, restrooms, and a few train artifacts. You can see the lower tunnel from the viewing area. The original tracks were much shorter and had a dangerous amount of slope. The tunnels lengthened that stretch of track allowing for a much more gentle grade. For more technical information see this Wikipedia article.
We stopped at the tunnels three times and on the last stop we waited about 45 minutes for a train. For us it was worth the wait. From the viewpoint the trains always come in from the left, loop around, and then exit to the left. The train then travels to the upper tunnel which you cannot see from the viewpoint. You can see the train moving in parallel in opposite directions.
The train comes in moving slowing from left to right roughly parallel to the viewpoint. It then enters the first spiral tunnel and exits the mountain above the rest of the train still traveling into the tunnel. The train then turns back roughly parallel the viewing area. You see the same train going in three directions at the same time.
If you like trains it is pretty mesmerizing watching a single train traveling in three different directions at the same time. The scenery around the tunnels is also pretty spectacular so be sure to enjoy the views when traveling there. The viewpoint contains a number of very fun and informative signs that provides more details about the tunnels.