Speed Zone 4:
Shasta Lake, and the realignment for it
Redding to Milepost 296
The original 1870's railroad track is either located under water, in Shasta Lake, or it is a biking and hiking trail to the Shasta Dam. The new alignment, in use since 1942, has cut away 7 miles of the former distance. But even though the realignment uses lots of tunnels and bridges, the description "highspeed line" does not fit. The state of California, which did the survey in 1925, was clearly interested in keeping costs down. The Shasta Lake realignment needed 15 million $, a comparable value to 200 million $ today. In terrain as difficult as this one, with several miles of track on bridge or in tunnel, there is reason to call this acceptable value.
South of Redding, the time saved, in comparison to the "Coast Starlight", is caused by
- cutting distance and curves away, by using the former Western Pacific.
- higher line speed.
- getting rid of slow runs in station areas.
- faster acceleration.
North of Redding, this changes completely. Speed is always restricted by track geometry. On the other hand, this means: Even the 7 inches of cant deficiency, that are expected for mixed operation of Talgos with heavy freight, will cut major amounts of travel time.
In the "good" parts, curve radius is 2864 feet, allowing 85 mph with tilting. In the "bad" parts, curve radius is 1432 feet, restricting to 60 mph with the assumed 3 inches of superelevation. Reasons for assuming certain values have been outlined on page 7 ff..
Speeds >79 mph require a different signal system, also to be installed in all freight engines. Considering the small gains within this speed zone, the author has calculated with 79 mph top speed, plus 60 and 70 mph in the parts with tighter curves.