Quote:
Originally Posted by Busy Bee
Could be the case.
Pretty sure it's 3%
Xpresswest is...5% max? That is if things haven't changed since the EIS.
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Direct from CHSR on grades.
https://hsr.ca.gov/docs/programs/eir...TM2_1_2R00.pdf
On the California High-Speed line, following grades are to be used:
• Desirable Grades shall be as low as reasonably practical, with a limit of 1.25%
• Maximum Grades: above 1.25% and shall be as low as practical up to 2.50
• Exceptional Grades: above 2.50% and shall be as low as practical up to 3.50%
Limitations on Length of Grades: Where the terrain permits, long grades steeper than the following shall not be used due to limits of braking capability of some of the proposed train sets:
• The average grade for any 6 km (3.7 mile) long section of the line shall be under 3.5%
• The average grade for any 10 km (6.2 mile) long section of the line shall be under 2.5%.
Limitations of Grade at Power Supply Phase Breaks: In European practice, due to catenary and signaling constraints, it is desirable to limit grades to 0.60% for 600 m (2,000 feet) on each side of a phase break.
Limitations of Speed on Grades: In European practice, speed on downgrades is constrained by train set braking limitations. The restriction is based on the average grade over any continuous length of 5,200m (17,100ft) along the line. The following speed limits for different grades are as determined in accordance with French standards:
• Grade between 3.0% and 3.5%: Vmax = 230 km/h (143 mph)
• Grade between 2.2% and 3.0%: Vmax = 270 km/h (168 mph)
• Grade between 1.6% and 2.2%: Vmax = 300 km/h (186 mph)
• Grade between 0.0% and 1.6%: Vmax = 350 km/h (217 mph)
How do you define ruling grade?
At speed, 220 mph, any grade the grade is limited to 1.6%. At 2.5% grade for 10 km the speed is limited to 168 mph, at 3.5% grade for 6 km the speed is limited to 143 mph.
And maybe surprising too many, the grade and speed limitation are caused by trains descending the grade, not for trains ascending the grade.