Southern Pacific choose 2.2% of grade for climbing out of the Sacramento River Canyon. Cantara Loop is the tightest curve within this part of the Shasta Route, its sharpness avoided the costs of a tunnel back then. The pictured settlements, a farm and a sawmill, do not exist any longer, and the Sacramento River got protection by a huge ugly guardrail, after a derailment on the bridge.
Postcard scan by John Mosbarger, used with permission. His postcard collection of the Shasta Route is found at his homepage. The postcard above can be found here in its original context.