In 1889, the Great Northern Railroad leased trackage rights through the Tumwater Canyon. In the agreement, the GN was required to maintain it, but the right-of-way remained the property of the CR & TN. Included in the agreement was the stipulation that any changes made would allow the CR & TN to use the Tumwater Canyon, resulting in a rather strange, but not all that uncommon, three rail arrangement. As engineering techniques improved, the GN was able to do away with the switchback and tunnel method employed by the CR & TN, replacing it with track that had a maximum 2.2% grade. In 1929, with the opening of the Great Northern's Cascade Tunnel, the line through the Tumwater canyon was electrified.