Saturday, September 02, 2017

Tunnel #6, the summit tunnel, did they have to build it?

From: "One Luckyduck"

I have wondered for years if all the time and expense (or a lot of it) could have been avoided, to build the original transcontinental line, much easier over the actual Donner Pass, and avoid the 2 year battle to build tunnel 6. I have hiked the area for decades and just finished another hike today of the original line over Donner Summit, thru tunnel 6 to Eder and back.

As a retired Engineer and Builder, I am very familiar with shooting grades, and major excavating to build houses on hillsides. It looks to me that the original builders could have turned 20' or so to the South just after crossing the Chinese Wall (heading West) and proceeded Westward on a bench just above the route of the old wagon road, (and subsequently the Lincoln Highway) over the summit, and proceed just to the North the the present lake Mary and end up in the same general summit location, just a little to the West. It would join the original route just West of the original turntable area. This looks like a no-brainer to me.

This would have saved a year and a half or more of precious building time, and been a substantial decrease in cost ... Could it have been required covertly to slow down the CPRR so they would end up having about the same track, and thus the same benefits as the UPRR?

Otherwise they would have been way ahead of the UPRR ...

I would really appreciate your thoughts on this, and any suggested reading concerning this question would be great, also. ...

—Tom Hallendorf, Soda Springs, California


Anonymous Anonymous said...

Don't know the merits of your proposed route alternative, but the fact that it took decades to locate the first transcontinental railroad route actually used, while many thought the project impossible, makes the claim that "This looks like a no-brainer to me" seem contrary to what actually historically occurred. They certainly didn't blast the Summit Tunnel with its enormous difficulty and expense, knowing that there was an easier alternative.

Deliberately slowing down the CPRR progress does not seem even remotely plausible for several reasons. The initial CPRR construction contemplated in the 1862 Pacific Railroad Act was only to the California border, and the final meeting point determination was conducted only months before the 1869 completion. The financial incentives favored building expeditiously, and the big four had their entire personal fortunes at risk, subjecting them to financial ruin if they failed.

9/03/2017 3:12 PM  
Anonymous Anonymous said...

From: "Wendell Huffman"

I believe the best answer (to the question why did they build the summit tunnel rather than on an alternate line?) that can be found 151 years after the fact is in Samuel Montague’s “Report of the Chief Engineer . . .” December 1865. He wrote: “Before commencing the location of this division [Summit to the State Line] the determination of the line at the Summit was a question of the utmost importance. Although the grades upon either slope admitted of a location with a very light cutting at the Summit Pass, the survey eastward, pointed to a lower summit grade, as calculated to greatly reduce the cost of construction, and afford better alignment over the most rugged portion of the line. After a careful consideration of the matter, a tunnel of seventeen hundred feet in length was determined upon.”

I take this to mean that, while the natural pass could be attained, the calculation of material to be removed on various alternate lines revealed that it would cost less to build the line they selected (the “as built” line) than it would have to build a grade at the necessarily higher elevation to attain the natural pass (approximately 50 feet higher). Apparently there was more rock to be removed on the higher grade in the difficult section between the summit and Strong’s ravine, than on the as-built line, including tunnel no. 6. Those guys measured the ground and did the math.

FWIW, based on Hopkins’s figure of $18/cubic yard, the summit tunnel cost $307,561.50. His figure of $1,000/day yields $346,000 for a total cost, but I suspect the daily cost varied with the number of active faces and whether or not they were working both headings and bottoms, or just one or the other, so that wasn't a constant.

As far as delaying the work, I do not think the summit tunnel made any real difference. The company did not even begin grading the roadbed above Cisco until the summer of 1867. By then the tunnels had been worked for several months. The delay in laying the railroad between Cisco and Truckee was in building the roadbed between Summit and Strong’s Ravine. As it was, that section was not opened until the late spring of 1868. Tunnel no. 6 took less than a year to build. However, even had they completed that section the previous fall, it would most likely have been abandoned to the weather over the winter of 1867-8. And, regardless, construction east of the state line was delayed for the construction of the Truckee bridges.


11/02/2017 5:20 PM  

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