For most of its first thirty miles, the Oregon, California and Eastern follows gentle grades to climb steadily into the forests of the eastern Klamath Basin. Engineers designed the railroad’s deepest cut at Milepost 13.67 to enter the valley at Pine Flat. Crews drilled and set dynamite charges to blast to a depth of forty feet through an ancient basalt flow. The curving right-of-way required weeks of labor, but provided fill to lay the railroad to the east of the cut. The origin of the name "Swede's Cut" is uncertain. Some claim it came from Swedish immigrants on the construction crew, while others say a Swede was killed there by a train. A later speed restriction ordered railmen not to exceed 15 MPH through Swede's Cut at MP 13.4.