Shasta Route speed zones
Part 2: Black Butte to Ashland
Curvature, possible speeds, and upgrade possibilities are very different along the Shasta Route. For good judgement, it is best to divide the route into speed zones. The following will be used:
- Zone 8: Black Butte to Edgewood
- This is a 2.2% grade down towards Shasta Valley, with a common curve radius of 574 feet. A slow section, and not easily improved without steepening the grade, which could be a problem for freight. The most effective improvement would be cutting off Black Butte Junction for passenger traffic, but the costs will hardly be justified.
- Zone 9: Shasta Valley
- Though currently a 25 mph territory, this can be the northern California race track, with 110 mph capability. Eliminating slow curves is most effective within a fast section. If any line upgrade is considered for Black Butte - Ashland, it has to happen within this speed zone first.
- Zone 10: Willow Creek, Klamath River, Cottonwood Creek
- This is curvy track, again with a common curve radius of 574 feet. Only the northernmost part has a steep grade. Several sections are straight, and several others are upgradeable at rather low cost, towards speeds like 60 mph or a little more. On a list of speed zones that should be upgraded with realignments between Black Butte and Ashland, this part would rank second.
- Zone 11: The Siskiyou Pass
- This is the worst section of all. Three loops with 410 feet radius, grades of up to 3.67% on the southern side, up to 3.4% on the northern side. Even with more power for the freight trains, as suggested in the strategy for the Siskiyou Line, the curves can't use maximum superelevation, because the freights will be too slow on this kind of grade. In addition, some transition curves would be too short for superelevation runoff anyway. Short of a base tunnel, this speed zone is close to unimprovable, beyond the speed effect of tilting trains and about 4 inches of superelevation.
- Zone 12: Down to the Rogue Valley
- Another slow section, with many 574 feet curves within the mountain section, before entering the Rogue Valley. Even the final run into Ashland is bisected by a single sharp curve. While this speed zone is considered upgradeable, the division of effect by costs gives a less favourable result. Possible exception might be that single curve close to Ashland.
How this document will list track speed
Speeds and times will be calculated for the existing trackbed and curve radius, but the article will point to the most cost-effective possibilities for upgrades like curve straightening.