The Tumwater Hydro Electric Project was constructed from 1907-1909. At that time, the hydro electric project was the largest west of Niagara Falls. The project was constructed by the Great Northern Railway Company to produce power for the electric locomotives traveling through the old Cascade tunnel on the Steven's Pass route.
Electrification of the three miles of line brought an end to the serious smoke and gas conditions in the tunnel resulting from the coal burning locomotives. Four 100-ton electric locomotives were in service on the trolly line to pull passenger and freight trains though the tunnel, which was abandoned in 1929 upon the construction of the new eight-mile-long Cascade Tunnel. The locomotives were the first in the United States to use regenerative braking, returning power to the lines on the downhill grade.
From the Tumwater Dam, water was delivered through a penstock to a powerhouse over two miles downstream. A bridge was constructed across the river to allow railroad access to the dam construction site. The bridge was then utilized to carry the penstock to the powerhouse. The bridge still stans and serves as a link to the old penstock route.
Crossing the bridge and following the trail will lead you to another cache "When Midnight Falls Upon the Castle". It is at the site of the old tunnel that the penstock came through. If you are careful you can climb up there and see the remains of the penstock.
If you stop at a time they are weighing and tagging the salmon you can see just how big some of the salmon are that go up this river. The workers were very kind to us and explained what they were doing and showed us the salmon.