Trains for the curvature of the Shasta Route -
the problem and the fastest solution

The old Shasta Route of the 19th century has had three parts with a huge number of very tight curves:

  1. The Sacramento River Canyon north of Redding.
  2. The crossing of the Siskiyou mountains.
  3. The Cow Creek Canyon in central Oregon.
In 1927, the Natron Cutoff bypassed the Siskiyou mountains and the Cow Creek Canyon. While it is a steep and curvy mountain route as well, it is better engineered with considerably less curvature and gentler grade than the Siskiyou crossing.

When the Shasta Dam was built, Southern Pacific replaced the southernmost track in the Sacramento River Canyon by a new line, that circles around Shasta Lake with lots of tunnels. Most of the Sacramento River Canyon was never bypassed, though. Between Delta, a few miles north of Shasta Lake, and Mott, a little bit south of Mount Shasta, there are 95 curves with a radius of 574 feet or less.

Map of curvature north of Dunsmuir
Curves between Dunsmuir and the siding at Small, only a short part of the distance with tight curvature.

Sensor-controlled tilting systems can have problems with such tight curvature. They work well with nice transition curves, accompanied with a superelevation ramp, that matches exactly to the transition curve. In very tight S-curvature, compromising might be unavoidable, though. The best solution for such situations is a tilting system, that does not rely on sensoring, but on a track database and position checks. Such trains have been developed in Japan and Spain.

Blue and sliver DMU under the roof of a snowshed.
JR Hokkaido DMU in a snowshed. This type 283 uses location-based tilting.

Japanese tilting trains, like those used for the "Super Ozora" service between Sapporo and Kushiro, would be very well suited to the Shasta Route, after adaption to normal gauge:

As explained on page 15, lightweight tilting DMUs loose their advantages by adaption to the FRA body shell strength ruleset. Without a modernization of the rules, operations like the "Super Ozora" of JR Hokkaido aren't feasible in the USA.

This document assumes, that usage of the fastest trains for the Shasta Route is no realistic option. Adapting to reality, the author will try to indentify the fastest kind of trainset for this route, that is compatible with the current FRA ruleset.

Unit conversion for text on this page.
574 feet radius 175 m radius 10 degrees of curvature
262 feet 80 m  
14.7 hp/ton 12 kW/metric ton  
48.4 tons 43900 kg  
81 mph 130 km/h  
1968 feet 600 m  

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Last modified: 2005-04-23