Monday, November 12, 2007

Steepest grade

From: "Nathaniel Wirth"

I was trying to find out what the steepest grade a train could climb with the first transcontinental railroad and what the steepest grade a locomotive can climb today? After all, I'd imagine that locomotives are more powerful now, and we can lay steeper tracks ...



Blogger CPRR Discussion Group said...

Maximum grade: 2.23%

"The Central Pacific tried to hold their grade to a 2% maximum grade, about 116 feet to the mile) preferably even a lesser grade if at all possible."

"In the present instance, the elevation of summit 7,000 feet above Sacramento, is reached by maximum grade of 105 feet per mile; showing a remarkable regularity of surface, without which the ascent could not have been accomplished with this grade." —Judah

1864: "Mr. COLLINS—What is the highest grade in crossing the summit which the Company will have to overcome? I mean the maximum grade; how many feet per mile?
Mr. STANFORD—The maximum grade is one hundred and five feet to the mile."

"Judah's survey crossed the State at nearly its narrowest part. It demonstrated that an elevation of 7,000 feet, with a base of only seventy miles, could be overcome with a maximum grade of one hundred and five feet per mile ... "

11/12/2007 9:48 AM  
Blogger CPRR Discussion Group said...

From: "Randy Hees"
Subject: Maximum grade

The theoredical maximum grade for steel (or iron) wheels on steel rails is 25%. This assumes all wheels are powered, with clean dry rails. While a locomotive could climb this grade, it couldn't pull anything, so the limits on grade are economic rather than a physical.

Generally mainline railroads have avoided grades over 4%, and prefer grades of less than 2%. Some logging lines had grades in the 8% or greater range, but these were considered exteme.

The original line over Donner Pass had grades of 2.4%. The Harriman built second track reduced some of that (but not all) to below 2%.

When the 1905 Western Pacific was built, it had a condition in its charter than maximum grades could not exceed 1%.

—Randy Hees

11/13/2007 11:48 AM  

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