This is just a small portion of this line, which was a subsidiary of the Great Northern. Twain's route into Seattle was slightly different that the later route.
Beginning in May 1890, the Seattle & Montana rail line was begun from Seattle north with three major rivers to cross -- the Snohomish, Stillaguamish, and the Skagit. Difficulties occurred. Some property owners bulked at selling, forcing condemnation. Heavy rains flooded the Stillaguamish River where track was to be laid along a route expected to be dry. At one point the drawbridge at the Stillaguamish River was condemned and had to be replaced.
The most difficult problems occurred along the stretch from Salmon Bay to the Snohomish River. The track was planned along this shoreline where erosion and waves constantly battered the light rockless soil. A Christmas day storm washed it out for a mile near Richmond Beach. On March 16, another storm washed out the new track near Edmonds and Mukilteo because the tracks were only four feet above the tide line. In addition, teredo worms infested the pilings along the salt water.
Finally, the track-laying machine was moved over to the Fairhaven & Southern road and track was laid from the north while the Stillaguamish River was being bridged.