Cascade Tunnel an Engineering Mistake (?)

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Cascade Tunnel an Engineering Mistake (?)
Posted by Murphy Siding on Wednesday, December 9, 2009 10:43 PM

     That's the title of an article in the current (Jan. 2010) Trains Magazine.  In a nutshell, the author, who worked for GN/BN/BNSF from 1963 to 1999, says that GN made a mistake in 1929 with its new tunnel and alignment.  He feels, that GN could have kept the old tunnel, and moved the west approach to the south side of the valley, and (?) stretch out the rise on the west side.  I'm skeptical.  His propsal seems to make sense to a know-nothing like me.  

      What I can't agree with, is his idea that GN goofed,  when the answer was so much simpler and less expensive.  He suggests that Ralph Budd pushed it through to have a showpiece tunnel engineering project on his railroad.  I believe, that even back in 1929, railroads had engineering and finance people on board who could help make the right decision.  Did they miss something?

    Related subject:  We keep discussing electrification.  Wouldn't the Cascade Tunnel be a prime candidate for it?

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Posted by creepycrank on Wednesday, December 9, 2009 11:11 PM
The new Cascade tunnel was electrified but GN couldn't ride of all that equipment fast enough after system wide dieselization. There are a couple of Columbia River hydro dams near Wenatchee at the bottom of the hill too. The electricity must have cost next to nothing. I've never seen an adequate explanation why this was done.
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Posted by schlimm on Wednesday, December 9, 2009 11:32 PM

 I wouldn't assume all the decisions made by corporate are the right ones for their company, much less society.  The classic economist, Adam Smith, is always held up as the paragon of the virtues ofmarket capitalism:  "The Invisible Hand."   Turns out he is often misquoted and thought decisions by big capitalists were often quite wrong for the public.

Today's Most Mischievous Misquotation - 98.03

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Posted by Paul_D_North_Jr on Thursday, December 10, 2009 8:19 AM

Murphy Siding
  [snip]  Related subject:  We keep discussing electrification.  Wouldn't the Cascade Tunnel be a prime candidate for it? 

Yes, from a 'need' perspective; but probably not from any other.

Clearances there are so close with a double-stack that overhead catenary is not possible to install.  See the photo at:

 http://www.flickr.com/photos/9131426@N06/4141586631/ 

However, I wonder if a 600 volt 3rd rail installation could be fit in at the lower side of the tunnel - see the photos at:

http://media-2.web.britannica.com/eb-media/45/124945-004-B7B379EA.jpg and

 http://www.railpictures.net/viewphoto.php?id=282858 

as in the New York City operations.  That could power either dedicated electrics for there only, or pick-up shoes on a western mountain version of the old New Haven dual-power FL-9's and whatever the Amtrak/ Metro-North current replacement is called - I believe it is P32AC-DM - see:

http://en.wikipedia.org/wiki/GE_Genesis

http://en.wikipedia.org/wiki/File:MNR_P32_Tremont.JPG and

 http://www.railpictures.net/viewphoto.php?id=265278 

Also, as an isolated electric operation, the electrics would have to be added on and taken off before and after going through the tunnel; otherwise, as a run-through the motive power districts and utilization would get all messed up.  On the other hand, as compared to the current wait for the bore to clear out, maybe that delay would be acceptable, or no worse.  Also, if a train has to wait for either an opposing or preceding move to clear through the tunnel, the connect and disconnect operations might not take all that much additional time anyway.

As much as I like electrification, I also have to wonder if this problem cannot be solved more economically by installing a souped-up ventilating system, and/or drilling a couple of ventilating shafts down from the top of the mountain, and installing high-power exhaust fans.

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Posted by zardoz on Thursday, December 10, 2009 9:16 AM

Paul_D_North_Jr
Also, as an isolated electric operation, the electrics would have to be added on and taken off before and after going through the tunnel; otherwise, as a run-through the motive power districts and utilization would get all messed up.  On the other hand, as compared to the current wait for the bore to clear out, maybe that delay would be acceptable, or no worse.  Also, if a train has to wait for either an opposing or preceding move to clear through the tunnel, the connect and disconnect operations might not take all that much additional time anyway.

Much would depend on the weather. If it is above 50 degrees, then yes, the add-ons would usually not take much extra time.  However, if the train has just bashed through numerous deck-high or greater snowdrifts and the locomotives are encrusted with packed snow and ice, and/or if the temperature has dropped well below freezing, then the add-on/take-off operation would frequently be unworkable.
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Posted by Bruce Kelly on Thursday, December 10, 2009 9:18 AM

The story begins falling apart with the sentence, "Because the sun directly strikes south-facing  peaks, they're susceptible to avalanches in the spring." Every study I have read on avalanches from the Rockies to the Cascades concludes that the main causes (to describe here in the most simple of terms) are periods of heavy snowfall followed by rain and/or sudden warming, often after cycles in which layers of ice or crusted snow have formed between larger snow slabs. None of these studies have ever mentioned exposure to sunlight. In fact, history says the 1910 Wellington avalanche cited in the story happened during rainfall, with thunder reported as a possible trigger.

The worst avalanche zone on the Stevens Pass route, for the railroad anyway, was the stretch between Wellington and Scenic on the loops which were abandoned in 1929. But the route proposed in this story would not protect trains from avalanches, as the author claims. Between Scenic and Wellington alone, his proposed route would take trains through 13 documented avalanche chutes, half of which are rated as "high" to "frequent" for slide potential. To say nothing of the large slide zone west of Deception Creek.

Before claiming the old Cascade Tunnel would afford BNSF greater capacity than the current Cascade Tunnel, there needs to be a more thorough comparison of the two. (I trust RWM and PDN will crunch the numbers against speed, emissions, etc., and give us the results.)

Old Cascade Tunnel: 2.63 miles long, 1.75 percent grade eastward, 3375-foot summit at east end.

New Cascade Tunnel: 7.79 miles long, 1.57 percent grade eastward, 2883-foot summit at east end.

20 minutes to clear fumes from new tunnel. How long to clear from old tunnel?

It seems to me the biggest shortcoming of both tunnels is their steep grade within, resulting in more exhaust build-up than should have been for a summit tunnel. Closest counterparts at Snoqualmie Pass and Stampede Pass have minimal grades within.

The story's comparison to Donner is like comparing apples to avacados. Donner in its day had two main lines over/through the summit. The most cursory look at their topography shows how CP (later SP) was able to follow ridgelines and hilltops, avoiding most avalanche areas, whereas GN through the Cascades had few such options.

 And please don't pluralize Sierra Nevada with an "s". Call them the Sierras, maybe.

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Posted by beaulieu on Thursday, December 10, 2009 9:25 AM
In a discussion on the Trainorders forum, a former Chief Dispatcher for BN who was in charge of the line through the Cascade Tunnel said that the Tunnel Ventilation issue being a limiting factor on line capacity is a bunch of Horsefeathers. If it was a problem, then adding a mid-tunnel door like the Mount MacDonald Tunnel on CP has would solve the problem at a reasonable cost. The problem is the gradient through the tunnel and the distance between the sidings at either end. If the freight trains were the length of the Empire Builder and powered the same amount, you could operate a lot more trains per day through the tunnel. Where some problems with ventilating occur, they happen because the Dispatcher doesn't begin the ventilation promptly. This can happen because the Dispatcher is distracted by things happening elsewhere on his district, or if he (she) just isn't paying attention. And then there is the need for MOW to have track time, not just on the tunnel itself, but also anywhere between Skykomish and Wenatchee.
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Posted by zardoz on Thursday, December 10, 2009 9:43 AM

Bruce Kelly
It seems to me the biggest shortcoming of both tunnels is their steep grade within, resulting in more exhaust build-up than should have been for a summit tunnel. Closest counterparts at Snoqualmie Pass and Stampede Pass have minimal grades within.

Consider, though, that even if the tunnel itself is graded flat, when the locomotives enter the tunnel, they are still working power pulling the train up whatever grade is on the approach to the tunnel.  If it  a short train, not too much of a problem; but if it is a long (9000'+) train, then the locomotives will be working power deep into the tunnel.
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Posted by Bruce Kelly on Thursday, December 10, 2009 9:55 AM
Cascade Tunnel is 1.57 percent eastbound, speed limit is 25mph, with a 20-minute delay for ventilation. Flathead Tunnel, similar in length to Cascade, is 0.62 percent eastbound, speed limit is 50mph, with no significant delay I'm aware of for ventilation.
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Posted by Paul_D_North_Jr on Thursday, December 10, 2009 10:02 AM

I remember reading in a ''history of American railroads'' book by either Holbrook or Stover about the latter-day locating engineer, Edward Gillette* (1854-1936), for whom the Burlington named a town in Wyoming, which we now know as the heart of the Powder River Basin coal and railroad operations.  (See, for example, the ''Gillette and Campbell County Historical Outline'' at: http://www.ccgov.net/departments/museum/gillette_history/index.html  and also "Gillette Photos - From Wyoming Tales and Trails - This page: Gillette, The coming of the Railroad, Edward Gillette." athttp://www.wyomingtalesandtrails.com/gillette2.html ).  One of his principles was to locate the railroad on the sunny, southward-facing side of a valley, to avoid the snow-build-up and avalanche risk.  The proposition in the article is directly contrary to that principle.

*He might be worthy of a thread and discussion all by himself.  He did write a book, which is referenced in the 2nd link above, as follows: Gillette, Edward, Locating the Iron Trail (Boston: Christopher Publishing House, 1925), pp. 74-76.  You just know I'm now going to be looking for a copy to borrow or buy . . . Big Smile  Any other comments or suggestions will be appreciated, since this thread is more likely than most to attract an audience with knowledge and interest in such matters.  Murphy, you're such an 'agitator' . . . Wink 

The rest of Bruce's comments seem 'right on' to me, and don't need much further elaboration.  The grade difference is negligible; more important is the elevation difference of almost 500 ft., tot he disadvanatge of the Old Cascade Tunnel.  A grade up to it of 1.75 % = 92.4 ft. per mile without any compensation for curvature; but deducting from that for, say, half of the track being curved on a typical 8-degree = 716 ft. radius curve at the rate of 0.04 % per degree would be 0.32 % in the curves or 0.16 % on average; accordingly, the actual rise/ increase in elevation on the compensated grade would be only about 1.60 % or 85 feet per mile.  Thus, to rise that 500 ft. would require an additional 5.9 miles; at 20 MPH that would add about 0.30 hr. or 18 minutes to each side of the tunnel, or 0.60 hr. = 36 minutes total.  As compared to that, the delay to add and remove electric helpers through the New Cascade Tunnel might be a 'wash' with regard to time. 

Obviously, the exhaust fumes could be cleared faster from the much shorter Old Cascade Tunnel, even without a ventilating system equivalent to that in the New Cascade Tunnel.  Therefore, the intervals between trains could be shortened up, and hence train frequency could be increased somewhat.  But first the Old Tunnel would have to be enlarged to clear double-stacks - and that ventilating system added, among other major capital expenditures.  I have no knowledge or recollection of either its lining or geological conditions - though I would not be surprised to learn that they are poor - but until BNSF got done with that, I expect that either electrifying with 3rd rail or greatly improving the ventilation at New Cascade Tunnel would be competitive, and likely more economical.

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Posted by schlimm on Thursday, December 10, 2009 10:06 AM

Bruce Kelly
The story begins falling apart with the sentence, "Because the sun directly strikes south-facing  peaks, they're susceptible to avalanches in the spring." Every study I have read on avalanches from the Rockies to the Cascades concludes that the main causes (to describe here in the most simple of terms) are periods of heavy snowfall followed by rain and/or sudden warming, often after cycles in which layers of ice or crusted snow have formed between larger snow slabs. None of these studies have ever mentioned exposure to sunlight. I

 

Although what you say is true, sunshine does have an important effect:  (from Wikipedia)

Slab avalanches account for around 90% of avalanche-related fatalities, and occur when there is a strong, cohesive layer of snow known as a slab. These are usually formed when falling snow is deposited by the wind on a lee slope, or when loose ground snow is transported elsewhere. When there is a failure in a weak layer, a fracture very rapidly propagates so that a large area, that can be hundreds of meters in extent and several meters thick, starts moving almost instantaneously.  A third starting type is an isothermal avalanche, which occurs when the snow pack becomes saturated by water. These tend to also start and spread out from a point.  

The snow pack on slopes with sunny exposures are strongly influenced by sunshine. Daily cycles of mild thawing and refreezing can stabilize the snow pack by promoting settlement, strong freeze thaw cycles will result in the formation of surface crusts during the night, and the formation of unstable isothermal snow during the day. Slopes in the lee of a ridge or other wind obstacle accumulate more snow and are more likely to include pockets of abnormally deep snow, wind slabs, and cornices, all of which, when disturbed, may trigger an avalanche. Conversely a windward slope will be bare of snow.

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Posted by Paul_D_North_Jr on Thursday, December 10, 2009 10:22 AM

I concur with what beaulieu and zardoz wrote above - they got to those very valid points before I could.  Thumbs Up

Flathead Tunnel is about 7 miles in length - references vary on that - but it appears to have a somewhat larger cross-section, which would promote train-induced ventilation.  See this photo:

http://www.rrpicturearchives.net/showPicture.aspx?id=756678

I'll see if I can find the typical actual dimensions to the top center of the crown and for width of each.

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Posted by Bruce Kelly on Thursday, December 10, 2009 10:44 AM
Re-doing Cascade Tunnel and Stevens Pass might become a moot point if the rumors of recent visitations by BNSF and WashDOT personnel to Snoqualmie Pass transpire into big investment there by Buffett and his bunch.
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Posted by Paul_D_North_Jr on Thursday, December 10, 2009 11:15 AM

Snoqualmie Pass was the Milwaukee Road's more southerly crossing, before it was abandoned and removed in the 1980s.

What are the pros and cons of that, from an operating persepctive, as best as we can discern them ?  Tunnels and clearances for double-stacks and multi-level auto-racks ?  Profile, grades and elevations ?  Bridges still in place ?  Connections to other BNSF lines - and which ones, with what kinds of traffic ?  Are they more or less congested than the present routes ?  Might this be part of a trade or swap to give up or sell other routes for commuter or passenger service Comparative distances and times across Washington state ?  A different/ better/ southern approach to the Seattle-Tacoma region ?  Any decent on-line traffic sources ?  Liklihood of serious NIMBY objections ?  Is any of it a trail now Etc., etc.

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Posted by Bruce Kelly on Thursday, December 10, 2009 1:13 PM

Snoqualmie would pose only a 0.7 percent climb against WB grain headed for Puget Sound ports, coal headed for Centralia, WA, and coal, petroleum coke, and potash headed for Vancouver, BC, area ports (Roberts Bank, Neptune Terminals), vs. 2.2 percent on either Stevens or Stampede (and vs. the long way around via Wishram and Vancouver, WA).

EB loaded stacks (if able to clear the tunnel and if Americans ever get back to buying foreign stuff in droves again) would face 1.74 percent on the west slope, which tapers down to only 0.4 percent through Snoqualmie Tunnel.

New trackage over Snoqualmie would likely connect to the current BNSF Stampede Sub near Easton on the east side of the mountains. Don't have my fleet of maps handy here at work to tell you exactly where the connection would be on the west side.

I believe there's one bridge on the west slope that would need rebuilding.

MILW grade is currently a trail. I imagine BNSF would face some major P.R., legal, and environmental hurdles to get that property back from the public.

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Posted by erikem on Friday, December 11, 2009 12:15 AM

Paul_D_North_Jr
Also, as an isolated electric operation, the electrics would have to be added on and taken off before and after going through the tunnel; otherwise, as a run-through the motive power districts and utilization would get all messed up.  On the other hand, as compared to the current wait for the bore to clear out, maybe that delay would be acceptable, or no worse.  Also, if a train has to wait for either an opposing or preceding move to clear through the tunnel, the connect and disconnect operations might not take all that much additional time anyway.

As much as I like electrification, I also have to wonder if this problem cannot be solved more economically by installing a souped-up ventilating system, and/or drilling a couple of ventilating shafts down from the top of the mountain, and installing high-power exhaust fans.

 

Or how about GE's hybrid locomotive???

IIRC, the battery pack on the hybrid was capable of putting out the equivalent of 2,000HP for one hour (the batteries have a power limit). One approach would be to run the locomotives with the diesel engine running at half power with the batteries making up the rest. While not in the same league as using electric locomotives, I would think a 40 to 50 % reduction in exhaust and waste heat would ease the ventilation requirements.

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Posted by Murphy Siding on Friday, December 11, 2009 11:47 AM

beaulieu
Where some problems with ventilating occur, they happen because the Dispatcher doesn't begin the ventilation promptly. This can happen because the Dispatcher is distracted by things happening elsewhere on his district, or if he (she) just isn't paying attention

  If it were an issue that affected train capacity, wouldn't it become a priority to see that the dispatcher began ventilation in a timely fashion?  How hard would it be to set up something that automatically alerts the dispatcher when the train clears the tunnel?

    If I read it right, the doors are closed (?) to ventilate?  how does that work?

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Posted by BNSFwatcher on Friday, December 11, 2009 1:36 PM

Item:  The Stampede Pass & Tunnel serves as a 'safety valve' for the Stevens Pass & Cascade Tunnel route.  The Stampede Pass line is still in service, but not used much.  I don't think BNSF management would consider changing the route to the old Cascade Tunnel route.  That's talking mega-$$$.  Item:  Mike Walker lists the Flathead Tunnel as 7.0 miles long.  I don't know the exact length.  My old BN ETT notes that it must be "flushed" after each train by the fan system.  Anyone know how long that takes?  Item:  I have a friend in Seattle that rides the old MILW Homestake Pass ROW on his motorcycle.  He says he never sees hikers (litterers) on the path, but you can bet there would be a huge howl if it was converted back to a railway, just for "General NIMBY drill".

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Posted by VerMontanan on Friday, December 11, 2009 1:38 PM

Mike Power has overlooked some important operating characteristics when he judged the Cascade Tunnel as “An Engineering Mistake” in the January 2010 issue of TRAINS.  In constructing Cascade Tunnel, Great Northern advertised that the route through the “new” (1929) tunnel would be 7.66 miles shorter than through the first tunnel.  Mike indicates that 19.85 miles of the old line could be abandoned, but 18.6 miles would have to be rebuilt under his proposal.  That means that his route would only save 1.25 miles, and that the “new” Cascade Tunnel route would be some 6.41 miles shorter than his proposal.

6.4 miles might not seem like much, but considering that track speed would be probably no more than 25 MPH (as it is today) and that the ruling grade would be 2.2 percent, most trains (especially those going uphill) would probably be going no faster than 20 MPH at best.  This equates to an additional 20 minutes of running time with his proposal.  Mike also failed to mention that the first Cascade Tunnel, though “only” 2.63 miles long, was an operation with electric locomotives to avoid the problem with fumes in the tunnel.  Since the first Cascade Tunnel was even slightly steeper (eastbound) than the “new” version, logic would dictate that under his proposal, the first Cascade Tunnel, when changed to a diesel locomotive operation, would also have needed a tunnel flush. 

      
The “new” tunnel can sometimes require up to 30 minutes for a flush after an eastbound train.  Since the first Cascade Tunnel was about 1/3 the distance of the “new” tunnel, estimating a 10-minute flush would not be unreasonable.  Adding a 10 minute flush time to the extra running time caused by a longer route (20 minutes) and you get 30 minutes, equal to an eastward flush with the “new” tunnel.  Therefore, there would be no capacity advantage to Mike’s proposal, and for westward trains, that require a minimal flush even with the longer tunnel (they’re going downhill), the  “new” tunnel’s shorter route would probably give it the advantage.  There would extra costs associated with both Mike’s proposal and the current operation to compare, but Mike’s proposal would not yield more capacity.

In the same vein, Mike says that the capacity of the “new” tunnel route dropped in 1956 when GN ended electric operations.  Again, not true; it actually increased.  The only way his statement could be true is if GN, in keeping its electric operation, would have extended electrification west from Skykomish to Everett, Seattle, and beyond.  Far outweighing the time restraints of a tunnel flush would be the need to stop and modify locomotive power at Skykomish and Wenatchee.  Taking an eastward train as an example, today’s trains depart origin with enough power to make the top of the hill.  Upon arrival at Wenatchee, some power may be cut to return west, but no power is cut or added at Skykomish.  In the days of an electrified operation, 100 percent of the inbound power would be useless for moving the train east from Skykomish. 

      
Given the increasing size of trains to today’s distributed power operations, the amount of power that would have to be available for an all-electric operation for the 33 trains Mike cites as the limit with today’s increased tonnages, would be a huge capital investment, yet these locomotives would be captive to a 72-mile segment of track; a very poor investment.  The amount of time necessary to add and cut power to EVERY train would probably exceed that of an eastbound tunnel flush by a factor of at least three, creating such bottlenecks at either end of the electrification that overall capacity would be much less than today’s operation.  In addition, there would also be the added costs of crews to perform the locomotive modifications, personnel to maintain the locomotives and other infrastructure associated with the electric operation, and the certain delays that would result when necessary to reposition locomotives from one side of the hill to the other when flows were not balanced.

The primary limiting factor for traffic through Cascade Tunnel today is the grade, rather than the tunnel, which is the case with most such heavy grades.  And, before I would label something as a “mistake,” I would also remember that of all the routes cresting the Cascades in Washington State ever constructed, only one has warranted continuous operation since it was built:  the “new” or current Cascade Tunnel.  Clearly, more than one railroad manager over the past 80 years has seen value in keeping it running.

 

**

This is the letter I wrote last week to TRAINS about Mike Power's article....it's probably too long to print.

All I said and and other stuff was basically covered in the excellent posts by Bruce Kelly and Paul North and others.

--Mark Meyer

(Mark- forgive me.  I added some artificial paragraph indentions to your text.  Otherwise, it was darn near impossible for folks with eyes like mine to read it on the screen.  -Norris (Murphy Siding)  )

 

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Posted by cx500 on Friday, December 11, 2009 1:43 PM

beaulieu
In a discussion on the Trainorders forum, a former Chief Dispatcher for BN who was in charge of the line through the Cascade Tunnel said that the Tunnel Ventilation issue being a limiting factor on line capacity is a bunch of Horsefeathers. If it was a problem, then adding a mid-tunnel door like the Mount MacDonald Tunnel on CP has would solve the problem at a reasonable cost. .....

 

The Mount MacDonald Tunnel has more than a door at mid-tunnel.  There are also fans, and a large diameter shaft about 1/4 mile deep leading down to the tunnel.  This shaft has a divider for the full length to keep the two halves of the tunnel separate during the ventilation process.  The tunnel alignment was given some curves so that the mid-tunnel facility could be located at a point where reaching the surface was feasible.  The cost for something similar for the Cascade Tunnel could easily by quite UNreasonable.

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Posted by VerMontanan on Friday, December 11, 2009 1:46 PM

Bruce Kelly

MILW grade is currently a trail. I imagine BNSF would face some major P.R., legal, and environmental hurdles to get that property back from the public.

 

This is true.  I believe the primary push in increasing capacity over Stampede or rebuilding over Snoqualmie will be how successful the Washington DOT is in expanding rail passenger service between Seattle and Portland in the future.  One way to add capacity is to get rid of all UP trains destined to and from Seattle and Tacoma and the heavy BNSF grain and coal trains to and from the same places that use this route.  But this will need another route over the mountains, and there it will not be the Cascade Tunnel route, because it has to be one that can be used by UP trains to and from the east.

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Posted by beaulieu on Friday, December 11, 2009 6:10 PM

Murphy Siding

beaulieu
Where some problems with ventilating occur, they happen because the Dispatcher doesn't begin the ventilation promptly. This can happen because the Dispatcher is distracted by things happening elsewhere on his district, or if he (she) just isn't paying attention

  If it were an issue that affected train capacity, wouldn't it become a priority to see that the dispatcher began ventilation in a timely fashion?  How hard would it be to set up something that automatically alerts the dispatcher when the train clears the tunnel?

    If I read it right, the doors are closed (?) to ventilate?  how does that work?

 

 

The normal position for the door which is located at the east (uphill) end of the tunnel is closed. When a train occupies a track circuit on either side of the door it opens and stays open until there is no train in the circuit. For an eastbound train climbing the grade through the tunnel the door is closed until it nears the east end and one of the two fans which are located at the east end is blowing air down towards the train. With a typical train pretty well filling the cross-section of the tunnel this keeps the exhaust fumes behind the locomotives, but does not pressurized the tunnel in front of the train. As soon as the last car of the EB train clears the tunnel the door will close and the Dispatcher should start the second fan. If this is done promptly, a WB train can leave the siding at the east end of the tunnel as soon as the EB clears the siding switch and the switch and signals clear for him. When the tunnel door opens for the WB the near end of the exhaust plume from the EB should have been pushed 1000' or so down the tunnel, when the tunnel door opens both fans should be shut off. The WB freight will act like a plunger and force the EB's exhaust plume ahead of itself while the turbulence around its cars will drag the plume from the WB behind it. Once the WB is completely in the tunnel the door again closes and the Dispatcher should start one fan. The problem requiring a time consuming flush of the tunnel comes when you have multiple EB trains closely following each other. WB trains act as natural method of flushing the tunnel of fumes, as since they are traveling downhill they generate relatively little exhaust themselves, and their speed is faster which creates its own airflow. 

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Posted by blue streak 1 on Friday, December 11, 2009 8:40 PM

beaulieu
WB trains act as natural method of flushing the tunnel of fumes, as since they are traveling downhill they generate relatively little exhaust themselves, and their speed is faster which creates its own airflow. 

This does bring up the required throttle setting for the dynamic brakes operating. Another thread a while back listed different setting for the dynamics to operate on different models. So the locomotive in the consist requiring the highest throttle setting for dynamics (coolin traction motors and grids) would be controlling. Anyone know what models are usually on this route and their settings?

A very expensive alternative would be for BNSF to temporarily shut down Stampede pass tunnel and enlarge it for all traffic including any future electrification; improve exhaust removal, provide sidings ( 10 - 16k long) on both side of tunnel for fluidity, improve signaling, Maybe a mid tunnel vent shaft?, etc.. Again another question would be what are the grades in this tunnel?   This would need to be weighed against rebuilding the MILW line.  Both capital costs and operating costs paybacks of each alternative would need to be carefully considered.

The NP route through Stampede would probably need earlier reconstruction because once P-NW traffic rebounds much that route will  be needed to prevent delays to traffic This will be certainly an early decision for BH that we will never be made aware of the internal process!.

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Posted by Paul_D_North_Jr on Friday, December 11, 2009 9:11 PM

I took another look at the map/ plan and profile accompanying this article, and realized a few more aspects that make the proposal less than desirable, in addition to those capably pointed out above, such as by Mark Meyer:

- By the proposed route cutting out that 1.25 miles on the 2.2% grade, there is about 145 ft. of vertical rise that would have to be made up someplace else.  It appears that a little of that would be accomplished by starting the proposed steeper grade a little further west of Skykomish, where the existing grade is still only 1.0 %.  But the rest would have to be made up in the other 18 miles or so of the proposed route, which will add about 0.10 to 0.15% to the existing 2.2 % grade up to the new tunnel's alignment to make the proposed grade around 2.3 to 2.35 %.  That's not a very attractive solution these days - a 2.2 % grade is pretty much unacceptable for new mainline construction, so why build or propose something that would be even a little worse to operate from a grade perspective, plus the added travel time as already noted above?

- The total rise or climb from sea level at Everett to the tunnel would increase by from 20 % to almost 25 % - from 2800+ ft. to 3300+ ft., or 500 ft.  That too seems to be burdening the operation with having to do more work and for a longer time than is otherwise necessary.

- A clarification:  Per the map, only the last 4 or 6 miles along the Tye River Valley of the westbound climb - in the vicinity of the 2 'loops' - would be moved by the proposal from the south-facing slopes to the north-facing slopes.  Most of the line west of Scenic is already on the north-facing slopes overlooking the Tye River, if the map is correct.  This was not clear to me after reading just the article.

- Paul North.

"This Fascinating Railroad Business" (title of 1943 book by Robert Selph Henry of the AAR)
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Posted by Railway Man on Friday, December 11, 2009 10:42 PM

 Constructing a new line requires STB approval ...

... which means it's a Federal Action ...

... which means NEPA kicks in and in all likelihood an environmental impact statement is required ,..

... which requires a statement of Purpose and Need, and alternatives analysis of routes ...

... which means that the Snoqualmie Pass Route would have a tough time proving that it's necessary or essential, as opposed to improving Stampede Pass.  Only if you could demonstrate that the environmental challenges of improving and operating Stampede Pass created more negative effects on air, water, endangered species, communities, safety, etc., would the outcome favor Snoqualmie Pass.  That I think is unlikely.

 RWM

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Posted by Railway Man on Friday, December 11, 2009 10:52 PM

 

Murphy Siding

beaulieu
Where some problems with ventilating occur, they happen because the Dispatcher doesn't begin the ventilation promptly. This can happen because the Dispatcher is distracted by things happening elsewhere on his district, or if he (she) just isn't paying attention

  If it were an issue that affected train capacity, wouldn't it become a priority to see that the dispatcher began ventilation in a timely fashion?  How hard would it be to set up something that automatically alerts the dispatcher when the train clears the tunnel?

I wouldn't obsess over this point.  It's a matter of setting priorities in a dispatching office, workload, manning levels, and costs.  If it's necessary to subdivide territories to reduce workload, that can be done.  Or, changing priorities to make one action higher priority over others -- other priorities might be calling trains at the right moment to eliminate terminal delay or loss of hours of service; issuing Track & Time to get maximum production out of maintenance-of-way forces; sorting out trainlists to give trains their work events.  It's not possible to do more than one thing at a time.

RWM

 

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Posted by beaulieu on Friday, December 11, 2009 11:41 PM

blue streak 1



A very expensive alternative would be for BNSF to temporarily shut down Stampede pass tunnel and enlarge it for all traffic including any future electrification; improve exhaust removal, provide sidings ( 10 - 16k long) on both side of tunnel for fluidity, improve signaling, Maybe a mid tunnel vent shaft?, etc.. Again another question would be what are the grades in this tunnel?   This would need to be weighed against rebuilding the MILW line.  Both capital costs and operating costs paybacks of each alternative would need to be carefully considered.

 

Stampede Tunnel wasn't named "Stampede Hell" by the crews that had to operate steam locomotives through it for nothing. The tunnel is peaked in the middle so it traps exhaust fumes. It has no ventilating system at the present time. It is a bit less than 2 miles long.

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Posted by Kevin C. Smith on Saturday, December 12, 2009 2:39 AM

 

For anyone that wants to wade through Locked Thread Oblivion, there are some informative...ah, discussions...about the comparative qualities of the old GN, NP & MILW lines through the Cascades, also electrification(s) and mention of the present Cascade Tunnel as an investment with negative return to date. But someone other than me is gonna have to tiptoe through those old minefields.
"Look at those high cars roll-finest sight in the world."
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Posted by Paul_D_North_Jr on Saturday, December 12, 2009 5:32 AM

Kevin C. Smith
  For anyone that wants to wade through Locked Thread Oblivion, there are some informative...ah, discussions... [snip] But someone other than me is gonna have to tiptoe through those old minefields. 

 

Laugh  Good idea, though.  Thumbs Up

Here's a short one from late January 2007 - featuring a couple of the 'usual suspects' - that somehow never went far enough down the road to Purgatory to actually get locked, though:

"BNSF's Stampede Pass" at - http://cs.trains.com/trccs/forums/p/85855/1014329.aspx#1014329 

- PDN.

"This Fascinating Railroad Business" (title of 1943 book by Robert Selph Henry of the AAR)
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Posted by Bruce Kelly on Saturday, December 12, 2009 9:49 AM

Thanks for linking back to that thread, Paul. There was some interesting debate, and some good points raised.

Blue Steak, to answer your question on Stampede Tunnel's grades, at this early hour while my family is still asleep, I've quietly pulled out the November 1997 Trains rather than bang around through my file cabinets in search of my source documents. I wrote in my story that from the approximate mid-point of the tunnel, grades descended west at 0.74 percent and east at 0.2 percent.

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