Page 73 of the January issue of Trains Magazine shows a Westbound BNSF Railway stack train fololwing the Flathead River through tunnel #4 in West Glacier, Montana. The tunnel appears to be as long as, say, 6 or 7 railcars. The amount of rock above the cars is perhaps 3 times the height of a loaded double stack car. The rock on the river side of the tunnel looks to be 2 to 3 times the width of the tunnel opening. Why would the builders have gone through all the work of building and maintaining a tunnel ,that looks like it could have easily been daylighteed?
I suspect you’d have to look at the technology available when the tunnel was built, not to mention the rock involved with the tunnelling. Since railroads rarely do things like that the expensive way (at least not on purpose) it’s possible that the cost of removing and moving all that rock/overburden was higher than simply drilling through.
Technogy of the time, need at the time of building, What happens to the interity of the hill/mountain if daylighted? Or what happens to the environment if eliminated? Daylight for one train a day or ten trains an hour? Everything looks and sounds easy until all factors are weighed.
Norris, you can rest assured that daylighting would be at least looked at, should the tunnel need to be enlarged in the future (think about the tunnels that recently disappeared on Cajon Pass).
And perhaps a “short” tunnel does not require very expensive maintenance.
I don’t know the costs comparison between boring another tunnel {roughly, a mile in lenth}, or go around with a massive excavation of land to bypass such tunnel.
The {auto}, tunnel {Laurel Hill}, in Pennsylvania, on Pennsy Turnpike is one example of what was done when they needed to create another 2 lanes to equal the turnpike’s 4 lanes…Original tunnel was just 2 lanes, and become a bottleneck to traffic. Grade was maintaned at 3% max. as was original route. But a terriffic amount of ground had to be excavated to create the bypass. It was possible to do there but not in some other tunnel locations.
Cost difference…Unknown to me.
And then there are the places were the original builders created a cut, and Mother Nature forced them to turn it into a Tunnel because once the underlying rock was exposed to the air it began to crumble and fill up the cut. The B&O with its very early construction had two cases like that in what is now West Virginia. The French also had a similar problem with the Fréjus Tunnel under the Alps to Italy, the majority of the very long tunnel was stable enough, but for a distance at the west end (French end) the rock began crumble filling the approach cut. They had to put a curve in the otherwise straight tunnel so as to pass through different rock strata, creating a new portal connecting to the existing line at a different point and also making the tunnel longer.
Couldn’t some tunnels in snow country be considered natural snow sheds? A deep cut where a tunnel had been daylighted would fill with snow pretty rapidly in a storm.
I agree with the above comment. {again using a highway comparison}, but I remember way back when the first part of the Pennsy Turnpike was built…There were comments of it’s design using tunnels…“The all weather highway”, the theory being, the highway eliminated crossing the higher elevations of the mountain ridges more susceptible to winter snow.
Using a by pass route {even with same max. grade}, got the route up and over the mountain rise, when building the by passes, and hence more snow…at least In Theory.
Just try moving all that overburden with a horse & fresno plus a few wagons. In 1885, mechanical excavators and bulldozers had not been invented by Holt et. al.
When BNSF removed the old CB&Q tunnel at Guernsey, WY in 1998, it was a tough call to justify the expense even then. (and a major accomplishment when they finished)
The geology of what is being removed, especially if groundwater is involved, is a major part of the decision. Then comes the issues of what do you do with the overburden and do you have the room to lay the slopes back without creating new problems (ask NS about Coshocton, PA or about several tunnels in the Heartland Corridor)…none of this is cheap.
First, since I don’t have that issue of the magazine handy - Is this the tunnel ? Both captions say it is Tunnel 4.0 (not my photos, of course):
http://www.railpictures.net/viewphoto.php?id=242535
http://www.railpictures.net/viewphoto.php?id=73533
Also - http://www.railpictures.net/viewphoto.php?id=243395 (no tunnel ID in caption)
Next: As several of the posts above have alluded to, the cost per cubic yard of rock excavation by hand-drilling and blasting methods ‘back in the day’ was probably pretty much the same regardless of whether the rock was in a closed bore such as a tunnel, or in an open cut. So given a choice between X cubic yards with a tunnel and 5X to 10X with an open cut, the tunnel would have been less yards hence less cost and less time. Note too that since this one is such a short tunnel, the ‘haul’ of the ‘waste’ or ‘spoil’ rock or debris - “muck” and “mucking”* are the usual technical terms for it, even if it all consists of broken rock fragments - from the working face to the portal to dump/ dispose of it would not have been long, hence would not have added much to the excavation costs.
[*Edited - Added those words, which I couldn’t think of yesterday - PDN.]
From a geotechnical perspective, these photos illustrate several aspects - though perhaps somewhat inconsistent - that would favor a tunnel over an open cut. First, in those photos such as this one - http://www.railpictures.net/viewphoto.php?id=243395 - can be seen some large blocky rocks in the ridge over the tunnel, which then drops off into the river. Those are likely igneous (volcanic) rocks such as basalt, which can be very har
Pardon the ignorant, but what is a “fresno”? I tried googling the term, but that yielded nothing except the city in California.
“Fresno Scraper”, the usually 1 or 2-horse (or mule)-drawn and of course much smaller ancestor of what is today usually called an earthmover, ‘motor scraper’, or ‘pan’, etc. See “The Fresno Scraper - Invented 1883 - A National Historic Mechanical [ ! - PDN.] Engineering Landmark”, at:
at http://files.asme.org/ASMEORG/Communities/History/Landmarks/5550.pdf
Google “Fresno Scraper”, and/ or see this link to the Historical Construction Equipment Association’s website for a short history of scrapers generally:
http://archives.hcea.net/index.php?p=digitallibrary/digitalcontent&id=10
- Paul North.
“A PRELIMINARY FEASIBILITY STUDY WAS CONDUCTED BY THE CALIFORNIA STATE DIVISION OF HIGHWAYS AND THE SANTA FE RAILWAY COMPANY OF POTENTIAL USES OF NUCLEAR EXPLOSIVES IN CONSTRUCTION PROJECTS FOR HIGHWAYS AND RAILROADS.”
http://pubsindex.trb.org/view.aspx?id=110048
With a big enough fire cracker, what could become a candidate for daylighting?
SOU rr day lighted a bunch of tunnels on the CNO&TP (rat hole) Cincinatti - Chatanooga due to severe clearance problems. some old tunnels would not even clear the new Big John hoppers SOU was proposiing. Of course SOU got the city of Cincinatti to fund much of the project in return for higher tarrifs.
Heck, the rest of that abstract - which is from 1964, of course - is the more interesting part [EMPHASIS ADDED - PDN]:
“THE STUDY WAS CONCERNED WITH DETERMINING THE FEASIBILITY OF EXCAVATING A CUT THROUGH THE BRISTOL MOUNTAINS NEAR AMBOY, CALIFORNIA, USING NUCLEAR EXPLOSIVES. THE PROPOSED RAILROAD ROUTE REQUIRED THE CONSTRUCTION OF A TWO MILE TUNNEL. THE PROPOSED CUT WOULD MORE OR LESS FOLLOW THE TUNNEL ALIGNMENT AND BE ABOUT 11,000 FEET LONG, WITH A MAXIMUM DEPTH OF ABOUT 350 FEET. CUTS HAVING DEPTHS OF LESS THAN 100 FEET WOULD BE EXCAVATED BY CONVENTIONAL METHODS FOR TECHNOLOGICAL AND ECONOMIC REASONS. GEOLOGICAL KNOWLEDGE OF THE AREA INDICATES THAT THE MEDIUM CONSISTS OF SOFT VOLCANIC ROCK UNDERLAIN BY META-GRANITE BEDROCK. USING CRATERING PARAMETERS FOR HARD ROCK, A TOTAL OF 22 NUCLEAR EXPLOSIVES RANGING IN YIELD FROM 20 TO 200 KILOTONS WOULD BE REQUIRED TO MAKE THE EXCAVATION. EXTENSIVE ON-SITE STUDIES ARE NECESSARY RELATED PRIMARILY TO SAFETY CONSIDERATIONS, INCLUDING DRILL HOLES, SEISMIC SURVEYS, HYDROLOGY INVESTIGATIONS, POPULATION SURVEYS, AND WEATHER SURVEYS.”
What was that proposed route about ? Where was it coming from and going to that a 2-mile tunnel would have been needed ?
22 “nuclear explosives” over 11,000 ft. is about 1 for every 500 ft. of length on average.
One might think that ‘blast-casting’ as practiced in the open-pit mines to loosen and move the overburden dirt and rock from above the desired mineral bed, over to the hole where it was just mined from, would be an ideal application for this - aside from the radioactivity problem, of course.
But I don’t think it would work too well for railroad applications, because of the ‘overbreak’ problem, among others. That occurs when the explosive is too powerful, and lo
Paul, when you mentioned, “Fresno,” I knew just what you were referring to–but I could not recall what I knew them as when I was growing up; but when you mentioned “pan,” I remembered seeing drag pans (usually bumping along on the way to or from where they were actually used). I wonder, how many of us have actually seen such a tool?
As to the question, “to daylight or not,” I recall one tunnel on the Southern’s ascent of the Blue Ridge, west of Old Fort, N. C., which was very short and seemed to be holding two mountains apart–would they fall together if the tunnel were daylighted?
Oh, OK - looks like maybe just a routine line relocation / straightening, from around Hector/ Pisgah (about 30 miles east-southeast of Barstow) through the Bristol Mountains as stated to the east-northeast for about 50 miles to around Goffs, which is about 20 miles west-northwest of Needles. But it was likely just an office-study/ map review/ desk-top/ ‘sand-table’ level study. Plus, it would have to go through the southern portion of the Mojave National Preserve, and perhaps the Providence Mountains State Recreation Area as well. And all in California these days ? Good luck with that . . . [:-^]
- Paul North.
The recently-completed Norfolk Southern “Heartland Corridor” clearance-improvement project for double-stacked container trains involved 28 tunnels. Here’s how they were handled, per the “fact Sheet” at this link:
http://www.thefutureneedsus.com/images/uploads/Heartland_Corridor_Fact_Sheet.pdf
"Methods used to increase tunnel clearances:
- Ex
[quote user=“Paul_D_North_Jr”]
Paul_D_North_Jr:
What was that proposed route about ? Where was it coming from and going to that a 2-mile tunnel would have been needed ?
Oh, OK - looks like maybe just a routine line relocation / straightening, from around Hector/ Pisgah (about 30 miles east-southeast of Barstow) through the Bristol Mountains as stated to the east-northeast for about 50 miles to around Goffs, which is about 20 miles west-northwest of Needles. But it was likely just an office-study/ map review/ desk-top/ ‘sand-table’ level study. Plus, it would have to go through the southern portion of the Mojave National Preserve, and perhaps the Providence Mountains State Recreation Area as well. And all in California these days ? Good luck with that . . .
- Paul North.
This was in the 1960’s and was a joint study with the Atomic Energy Commission (or what ever it was called then), the Federal and State Transportation Departments and the Santa Fe Railway. It was made to determine if atomic explosions could be used for peaceful purposes, The tunnel was to be eliminated with a huge excavation created by the explosion(s). There is much more info about this. What was shown above was just part of the Santa Fe participation in the writing and the names shown were at that time Santa Fe engineers.
The concept was to locate both I- 40 and the railroad in the same ROW. Many factors including politics, treaties and money,.intervened. In the 1960’s we could at least talk about such concepts.
The 2-page NS article from January-February 2009 at the link below says that 1 tunnel was bypassed, and another one had its roof completely removed, which I take to mean ‘daylighting’:
http://www.thefutureneedsus.com/images/uploads/bizNS1.pdf
Another article from The Virginian-Pilot by Robert McCabe dated May 2, 2010 mentioned the bypassing of 1 tunnel, but not the daylighting:
In any event, “day-lighting” was not the preferred method to improve clearances in almost all of these tunnels.
- Paul North.