When the railway track first crossed the pass back in 1884, it shot down the valley of Kicking Horse River at a precarious 4.5% grade, causing a few derailments. This led to the construction of two spiral tunnels in 1909. A few kilometres east of Field, a lookout point is equipped with information panels relating the history of the CPR's upper and lower tunnels. The entrance to the lower tunnel in Mt. Ogden can be seen from this vantage point.