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Cascade Tunnel an Engineering Mistake (?)

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Posted by VerMontanan on Friday, January 1, 2021 5:55 PM

Mac said, “Traffic on the Cascade tunnel line is first and foremost intermodal to and from South Seattle (domestic) Port of Seattle, and Port of Tacoma. Many of these trains are DPU powered. I do not know where the DPUs come on and off, but would bet the vast majority are on/off at Hauser Yard 15 miles or so east of Spokane where every train to and from Vancouver WA and Puget Sound points gets fueled westward and eastward.”

You would lose that bet.  DP units are rarely added at Hauser or Spokane simply because it’s too busy to do it there due to the fueling function.  And not every train gets fueled at Hauser Yard.  They try to do as many as possible, but it’s often a function of capacity, and trains like coal empties regular get fueled in Missoula.  But it’s commonplace with congestion to “check the fuel” and continue east to places like Havre.

As to where the DP is added, this varies widely.  Unit trains tend to be that way out of destination.  Trains from Whitefish get add-on units as necessary at Great Falls or Havre.  Intermodal trains run the full gamut.  They come with distributed power out of St. Paul, add at Minot, Havre, or Wenatchee.   Havre is the most-likely spot for adding power (distributed power or not) because it is the roundhouse for the west end of the Northern Transcontinental.  (Interbay has a roundhouse, but they work mostly on power used for yard, locals, and intradivisional runs.)  Where the DP power is cut depends on the current operation.  When power is exceptionally tight, Wenatchee is the best place to cut off eastward intermodal trains (and then they get helped Essex to Summit).  Power is then added to westward trains and that allows the train to operate to Wenatchee with the absolute minimum power.  Of course, the standard today is to do as little power modification en route, so power can continue east to Havre or Minot (both inspection points) to avoid the helper cost at Essex.  It all just depends on the need.  It’s not usual to let power run through to Havre simply to have some available for origin grain trains or unit trains which require add-on power.

Mac said, “The best way to increase capacity is to get the Empire Builder to go away. That has not happened for 50 years and there is no reason to expect Congress to quit pouring money down the ATK rathole, so assume that particular burden will not go away.”

Your anti-Amtrak bias is well-known, but it specifically is inappropriate here.  That it’s a short train that operates at track speed and takes up less capacity relative to other trains notwithstanding, the reality is that it’s a train that needs to be figured into the mix.  That’s what railroaders do.

Mac said, “The line handles one pair of mixed carload trains between Everett and Spokane/Hauser. All else is intermodal. These trains have long operated in DPU mode, itself increasing capacity for intermodal traffic via Stevens Pass.”

Not everything else is intermodal.  Coal and crude empties trains from north of Everett routinely operate via Wenatchee to avoid the Seattle terminal.

Mac said, “There are Bulk traffic, grain, coal, and oil unit trains that would/should use the route IFF it had the capacity, which it has not for any years. BN's first response was to route carload and bulk, and even intermodal via Vancouver Washington then to the two main track line between Vancouver WA and Everett. Converting the intermodal trains to DPU seems to have been enough to get them off the long mile, longer time route via Vancouver WA. Today oil and coal trains continue up the single track former GN main line to their destinations north of Everett and south of Vancouver BC.

The bad thing about this route is that it is significantly longer than the Cascade tunnel route, say about 180 miles longer Spokane to Seattle. The good thing is that the ruling grade is significantly less, 1% vs 2.2%, so required horsepower per ton/train is only half what is needed to lift loads over the mountain. The reduction in horsepower hours is less than 50% due to the excess mileage. That excess mileage also generates higher operating costs than would otherwise be the case, but when the capital investment solution is very expensive, you live with higher than ideal operating costs.”

Nope.  Not the case, and we know this because running today’s unit trains via Wenatchee (and via Ellensburg) has been tried and proven to be fantastically inefficient.  I know specifically because my team at BNSF was tasked with providing the locomotive power for it.  The “reduction in horsepower hours is less than 50% due to the excess mileage” is especially inaccurate.  Mac fails to mention that trains via Wenatchee need 100% to 167% more power than those operating via Wishram and Vancouver.  (These trains normally operate with 3 or 4 units, mostly depending on origin).   That’s a huge expense.  When this was done in the 2010s, the additional power (most of the time) was added at Wenatchee.  The trains were grain trains to Seattle and Tacoma.  Not counting station dwell at Wenatchee to configure the power (most trains departed 3X3X2 distributed power), the average locomotive took 49 hours to get back to Wenatchee to be in place for another grain train.  On average, two grain trains were operated daily, so that would mean that more than two days would elapse (with two trains each day) before the extra power required for this rotation could again be in place.  That meant a minimum of 20 to 25 locomotives (depending on whether 4 or 5 units were added), a significant amount of resources.  Running time via Wenatchee wasn’t great, either.  During the test period, trains destined to Seattle were a whopping 8 minutes faster via Wenatchee and took 4 hours LONGER en route to Tacoma.  Crew costs were higher via Wenatchee, too, because a crew had to be called at Wenatchee just to configure the power on the train (the big delay is cutting in the mid-train DP).  Trains for Tacoma took a crew just to get the train from Seattle to Tacoma and additional delay to cut out the mid-train DP locomotives because TEMCO wouldn’t take it that way. 

For unit coal and crude destined to Fidalgo, Cherry Point, Arco, or Roberts Bank, the inefficiency of a routing through Wenatchee might not be as acute, simply because the comparative route miles are fewer.  But, the number of additional locomotive resources is similar, and – with the exception of Fidalgo – the trains are going just as far or father with that extra power than the Seattle and Tacoma grain trains.  In a perfect world with unlimited capacity, crews, and flexibility, additional power added to these trains at Wenatchee would be cut at Gold Bar to be immediately moved back to Wenatchee for another train.  But another crew would be required to remove mid-train DP units and the work would restrict the fluidity of the other traffic on the route while the train was doing the work.  Then try to find an eastward train to Wenatchee with a crew that has enough time to stop and pick up the power….good luck.

The beauty of unit train operations on BNSF in the Pacific Northwest is that it is pretty much perfectly balanced:  The loaded trains arrive from Montana with enough power to get the train to destination, handle the corresponding empties back to where the train will again be loaded, that’s sufficient power to launch yet another load, and the cycle continues.  Adding a segment that doubles (or more) the power requirement adds cost on top of cost.  And, there’s one other big cost:  The cost of occupying track space.  When trains have to cut in distributed power mid-train or add to the rear end and other locomotive work in general, scarce yard space is used for extended periods of time that can’t be used by other trains.  And at Wenatchee, this can usually be cutting off eastward to trains to add to westward intermodal trains.  Bottom line:  Adding trains to any route with significant power modifications is the perfect thing to do if you want to stifle fluidity.

Mac said, “A few years ago the BNSF and the operating crafts entered into an agreement for a three legged crew district; Pasco to Vancouver WA, Vancouver to Seattle, and Seattle to Pasco. Each crew works those segments in that order.”
Nope.  Auburn is home, so Auburn to Pasco is the first leg.

Mac said, “There has been discussion of the former MILW Snoqualmie Pass line. It is a reasonable alternative between Easton and Renton. The problem is that while this middle is OK, the ends are not. On the West end, the line features street running for about a mile through downtown Renton.”

Actually, it’s a rare proponent of this route that even mentions the route through Renton.  The street running is the least of the problems.  The major ones are the areas in Renton that have been completely developed as well as several sections east of Renton along Washington Highway 169, which has been widened significantly.  I believe that there is zero chance of the Milwaukee route being revived, but for those who fantasize, the general consensus is that a 3- or 4-mile connection would be constructed from the Milwaukee line at Landsburg to the ex-NP line near Ravensdale. 

Mac said, “I give you all lots of points for imagination, but not much for practicality.”

Agreed.

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Posted by SD70Dude on Friday, January 1, 2021 6:23 PM

Thank you for the reality check Mark, I was hoping you would see this thread and comment.

Greetings from Alberta

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Posted by PNWRMNM on Saturday, January 2, 2021 8:24 AM

To the extent Mark's explanation differs from mine, use his. His knowledge of power use is much better than mine and his trips to Renton area are probably more recent.

As to power via the Columbia River Gorge/Vancvouver WA vs Stevens or Stampede passes, the mountains will require double to 2.5 times the power per ton that the Gorge will. Spokane to Puget Sound via the Gorge is 1% ruling grades Spokane to Pasco and over Napavine Hill. In DC motor days you could figure 1 HPPT. Over the mountains was about 2.5 HPPT. I do not know what the figures are today with AC, but it looks to be about the same ratio today.

While AC power can lug along at 2 MPH, you need to put enough power on the train to move with reasonable dispatch up the grades. Five or six hours from Skykomish to Scenic will limit line capacity more than the time between Scenic and Berne does now. Again the fundamental point that running time between stations is what counts.

Mark's details about power experiments confirm the overall point I was trying to make, which is that since 1970 BN and BNSF have provided enough capacity to handle the traffic without expensive engineering solutions or exotic geegas.

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Posted by blue streak 1 on Saturday, January 2, 2021 11:36 AM

Battery locos or even an isolated electric distric are going to be just a pain in the neck.  Since ventilation is a problem why not sink one or two ventilation shafts at the mid point or 1/3 point to ventilate the tunnel more quickly ?  That way ventilation for tracks alreaady cleared behind train could start.  Would require doors at mid point or 1/2 points.  Once a train cleared a shaft it could suck smoke away from locos.  definitely would require reversible fans to help clear tunnel. 

  If traffic increases over the next  ( number unknown ) years causing this to become  a necessity then additional sidings are going to be needed especially close to the tunnel.

EDIT.  Additional shafts would need capacity to ventilate tunnel from both directions.  also maybe ventilation at west end ?

Initial capital costs up front  may be high. Certainly more feasible in long run reducing  overall operating costs

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Posted by Overmod on Saturday, January 2, 2021 11:50 AM

blue streak 1

Battery locos are going to be just a pain in the neck.  Since ventilation is a problem why not sink one or two ventilation shafts at the mid point or 1/3 point to ventilate the tunnel more quickly ?  That way ventilation for tracks alreaady cleared behind train could start.  Would require doors at mid point or 1/2 points.  Once a train cleared a shaft it could suck smoke away from locos.  definitely would require reversible fans to help clear tunnel.

(1) Tell me the cost of sinking shafts and upgrading and maintaining ventilation plant vs. the marginal cost of constructing hybrid power with uses elsewhere.

(2) There is no guarantee that meaningful reductions in time would result from one or two (how cavalierly we use numbers!) new vent shafts.  There is still a cycle time, and perhaps issues for DPs in a given consist, compared to a 'solution' that reduces or eliminates substantial gas and perhaps heat in any part of the bore to begin with.

I thoroughly agree that trying to do that entirely with battery (I.e. enough 'hybrid' storage to take at least the head end through the bore with engines off or isolated) is less attractive than dual-mode-lite for only slightly less investment in the power and initially very limited mandatory investment in 'diesel-power-equivalent' external conductor  in the tunnel area.

This is a generic argument about moving traffic through tunnels, not an organized colorista improvement scheme for traffic in the actual Pacific Northwest.  I am reminded of the line in the Tom Lehrer song about "die Rockets go up, who cares where they come down" -- that's not my department, either.  (Not to disparage the actual dueling Pacific Northwest experts in any respect.)

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Posted by Shadow the Cats owner on Saturday, January 2, 2021 3:42 PM

This might give you an idea of what the extra expenses are for the railroad based on what it costs an OTR carrier to run in the mountains.  We have a dedicated team that runs out to SLC and back on an almost daily basis.  Now going west they average about 1 MPG LESS than coming back East.  Why the climbing of the mountains in WY and UT plus the gradual climbing going across NE.   Their loads weigh the same each way trailers are maintained on a by monthly basis where they are shopped at our shop.  Truck for now is a 2019 KW we have a new 2020 top of the line Volvo on order for them.  Sorry I deal with figures all day long on MPG and you can be amazed on what can effect it.  I discovered that we got worse MPG from a certain fuel stop chain than another and so we stopped getting fuel from them a .5 MPG average adds up very quickly on 250 trucks and can costs us thousands a week in extra expenses.  

 

How the BNSF is going to have to deal with the Cascade Tunnel is simple they can not bypass it due to the terrian there.  They can not double track it way to narrow of a pass in that area and the local enviromential wack jobs being the PNW would never allow anything that extreme.  Forget about redoing the orginal for the same reason to allow a bypass for this one even though the railroad could technically claim they are just reactivating an old route if they never filed a formal abandonment of the old line.  It might be a good westbound only route why going downhill all the way therefore.  Just would need to redo the snowshed protection.  

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Posted by Backshop on Saturday, January 2, 2021 7:03 PM

I'm sure fuel mileage is also affected at least as much by the predominant westerly winds.

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Posted by BaltACD on Saturday, January 2, 2021 7:12 PM

Shadow the Cats owner
This might give you an idea of what the extra expenses are for the railroad based on what it costs an OTR carrier to run in the mountains.  We have a dedicated team that runs out to SLC and back on an almost daily basis.  Now going west they average about 1 MPG LESS than coming back East.  Why the climbing of the mountains in WY and UT plus the gradual climbing going across NE.   Their loads weigh the same each way trailers are maintained on a by monthly basis where they are shopped at our shop.  Truck for now is a 2019 KW we have a new 2020 top of the line Volvo on order for them.  Sorry I deal with figures all day long on MPG and you can be amazed on what can effect it.  I discovered that we got worse MPG from a certain fuel stop chain than another and so we stopped getting fuel from them a .5 MPG average adds up very quickly on 250 trucks and can costs us thousands a week in extra expenses.  

Of course there was one truck stop chain that was convicted of cheating their customers on the amount of fuel pumped vs the amount of fuel billed.

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Posted by VerMontanan on Saturday, January 2, 2021 7:36 PM

PNWRMNM

Mark's details about power experiments confirm the overall point I was trying to make, which is that since 1970 BN and BNSF have provided enough capacity to handle the traffic without expensive engineering solutions or exotic geegas.

 

Sorry, but sounds like a bit of backpedaling here. Referencing the Stevens Pass route, Mac said, “There are Bulk traffic, grain, coal, and oil unit trains that would/should use the route IFF it had the capacity” suggesting that should be the preferred route, and also then stated, “The reduction in horsepower hours is less than 50% due to the excess mileage. That excess mileage also generates higher operating costs than would otherwise be the case, but when the capital investment solution is very expensive, you live with higher than ideal operating costs.”  While both statements have been shown to be untrue, it’s odd that Mac would then admit “since 1970 BN and BNSF have provided enough capacity to handle the traffic without expensive engineering solutions.”  I guess I would ask: If BNSF has provided enough capacity, why promote doing it differently?

There have been “expensive engineering solutions” in the Pacific Northwest to enhance traffic flow, though admittedly “expensive” is subjective.  BNSF has laid out a lot of money for improvements in Washington State along the route of unit trains.  Sidings and or 2 MT CTC have been lengthened and created between Spokane and Vancouver, and the extra capacity added to accommodate Amtrak Cascades and Sounder trains have enhanced fluidity between Vancouver and Everett.  And let’s not forget the $200 million or so for opening the Stampede Pass route which ultimately made the current operating scenario work.  While some improvements were made along the Stevens Pass route including in Cascade Tunnel, the obvious intent was to focus elsewhere.  In the end, “expensive engineering solutions” did occur.  Having said that, three years ago BNSF completed raising clearance in tunnels south of Bellingham to accommodate doublestack equipment from the port of Vancouver should BNSF wish to attempt to wrest some business from CN or CP.  Hasn’t happened yet that I know of, but since such traffic would go east at Everett, it shows acknowledgement that current capacity over Stevens Pass is sufficient.  It also shows that there is some capacity available for new traffic, and that still hasn’t lured any loaded unit trains to the route. 

The enhancements to infrastructure in Washington State individually don’t rise to the glitziness of a second Sandpoint bridge or doubletracking the railroad from Minot to Williston for sure, but over the course of the past two decades, similar billions of dollars have been spent.  And despite these “expensive engineering solutions,” there are myriad valid reasons loaded unit trains still don’t operate via Wenatchee.

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Posted by SD60MAC9500 on Monday, January 4, 2021 10:18 AM
 

VerMontanan

 

Having said that, three years ago BNSF completed raising clearance in tunnels south of Bellingham to accommodate doublestack equipment from the port of Vancouver should BNSF wish to attempt to wrest some business from CN or CP.  Hasn’t happened yet that I know of, but since such traffic would go east at Everett, it shows acknowledgement that current capacity over Stevens Pass is sufficient. 

Mark I'm glad you mentioned this. I always had it in my mind that maybe one day BNSF would make a go at the Port of Vancouver's container traffic. It always appeared to be a logical market for BNSF to crack. Is there any coal still going to Roberts Bank, B.C.?

 
 
Rahhhhhhhhh!!!!
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Posted by Bruce Kelly on Monday, January 4, 2021 10:59 AM

Yes, there is coal still going to Roberts Bank.

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Posted by MidlandMike on Monday, January 18, 2021 8:53 PM

Bruce Kelly
He (and others) said that the running time between the sidings determines capacity. Those being the sidings at opposite ends of the tunnel, Scenic and Berne,... Maximum authorized speed between Scenic and Berne is 30mph passenger and 25mph freight.

In your Februrary Trains article on the Flathead Tunnel, you mention that its tunnel speed limit is 50 mph.  Also it takes 15-20 minutes to flush fumes.  Can I presume this is why Flathead Tunnel (which is 9/10 the length of Cascade) still handles 40 trains a day?  Could it handle more?

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Posted by Erik_Mag on Monday, January 18, 2021 9:29 PM

One difference between Flathead and Cascade is that Flathead has a 0.4% grade versus the 1.8% (?) grade in the Cascade tunnel. I'm assuming that Flathead has the higher speed limit due to the much lower gradient.

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Posted by SD60MAC9500 on Tuesday, January 19, 2021 6:35 AM
 

Erik_Mag

One difference between Flathead and Cascade is that Flathead has a 0.4% grade versus the 1.8% (?) grade in the Cascade tunnel. I'm assuming that Flathead has the higher speed limit due to the much lower gradient.

 

Cascade Tunnels grade is 1.57%.

 
 
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Posted by Erik_Mag on Tuesday, January 19, 2021 9:43 AM

SD60MAC9500
 

Cascade Tunnels grade is 1.57%.

Thanks.

Still close to a factor of 4 steeper than the Flathead tunnel, which makes big difference in safe downgrade speeds as well as achieveable upgrade speeds.

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Posted by Overmod on Tuesday, January 19, 2021 10:28 AM

Erik_Mag
Still close to a factor of 4 steeper than the Flathead tunnel, which makes big difference in safe downgrade speeds as well as achieveable upgrade speeds.

All the more reason why correct 'snapping' enabled even by dual-mode-lite levels of electrification, combined with proper regenerative or storage braking and CBTC, would vastly reduce any fixed delay due to the tunnel itself or its approaches.

The issue of short-following fleeting remains an issue for practical throughput, again hinging somewhat on the ability of CBTC to flexibly extend "block" length without compromising the ability to run alternating-direction traffic as a couple of posters have advocated.

The use of fixed (a larger version of "wayside") storage for trains that alternate through the tunnel becomes an interesting subject for Erik to contemplate.  Even a magnetic-bearing flywheel arrangement might have enough persistence to accommodate 'pairs' of downhill/uphill traffic to substantially reduce peak required external power supply for the uphill running, or permit more cost-effective 'full electric' operation for the power actually transiting the bore.

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Posted by Erik_Mag on Tuesday, January 19, 2021 2:23 PM

My comment about safe downgrade speeds has to do with brake fade. Assuming a train resistance of 0.2% of weight, a grade of 0.4% (Flathead tunnel) would need 0.2% of train weight worth of braking effort as opposed to ~1.4% of train weight worth of braking effort in the Cascade tunnel.

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Posted by Bruce Kelly on Tuesday, January 19, 2021 2:39 PM

MidlandMike, I've seen past figures from BNSF that say the practical capacity of Flathead Tunnel is something like 44 trains per day. It would not surprise me if there have been occasions when the tunnel has handled more than that. Mark Meyer can speak with more authority, experience, and current insight into this.

A more detailed explanation of the geography of the Flathead Tunnel area and its impact on train operations was provided in my earlier story on the subject, in another magazine, a little over a year ago.

My son and I have observed during our visits there in peak season / fall rush months how Flathead Tunnel's flush times can take a toll on the flow of traffic, hence BNSF's recent efforts to shorten those times.

Whenever there was a fleet of three or more eastbounds making good speed toward the tunnel, the first one would roll right through (if the previous flush was finished), while the second train would come to a stop at the east switch at Rock Creek (the siding just west of the tunnel), the third train would stop at the west switch at Rock Creek, and any other following eastbounds would be stopping somewhere behind all of that. After the first train exited the east portal, the flush would begin (10 to 20 minutes), and once the flush was finished the second eastbound would enter the tunnel while the third eastbound pulled up to wait, and so on for any others following behind.

By the time this whole process has played out, even if there have been no westbounds routed through, a third or fourth train in an eastbound fleet can see upwards of an hour or more of total delay when you add up the running times and flush times of the trains ahead of it, including the time it takes for standing trains to get moving again and moving trains to ease to another stop.

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Posted by BaltACD on Tuesday, January 19, 2021 3:17 PM

Bruce Kelly
By the time this whole process has played out, even if there have been no westbounds routed through, a third or fourth train in an eastbound fleet can see upwards of an hour or more of total delay when you add up the running times and flush times of the trains ahead of it, including the time it takes for standing trains to get moving again and moving trains to ease to another stop.

Smart begins when the calling time for the crews of the trains are considered and have to be based on the tunnel transit conditions.

Don't call the trains on 10 minute headway when you know you are going to have 40 minute cycle time on the tunnel operation.

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Posted by Bruce Kelly on Wednesday, January 20, 2021 8:26 AM

In theory, spacing train departures out of Yardley or Hauser to the west or even Whitefish (which is much closer to the tunnel) to the east in order to minimize delay at the tunnel sounds nice, and on some occasions there may have even be an effort toward doing that. But in actual practice, it would often become futile. 

In the case of that eastbound fleet I described, consider how their journeys likely started at either Yardley or Hauser. More like Hauser, since the vast majority of eastbounds are recrewed there, rather than at Yardley. But both yards face the pressure of having to keep trains moving through on the their adjacent main lines. At Hauser, that includes trains that refuel and recrew on Mains 3-6. Hauser can get by with letting a train or two occupy a fuel track for hours, well beyond the nominal 10-20 minutes it takes to fuel the head end (and additional time to respot and fuel DPUs), as long as other fuel tracks remain fluid. But when traffic is heavy, there's rarely the luxury to let trains sit. It's quite common to have two, three, even four eastbounds all call up the dispatcher at about the same time, saying that they're ready to depart.

So, even if the best laid plans of dispatchers and crew callers could manage to somehow send a fleet of eastbounds out of Hauser on generous 30-minute headways, they could easily stack up behind each other at East Algoma (the current east end of two main tracks on the Funnel) if there's a fleet of WBs approaching Sandoint off both the Hi Line and MRL, or just a single Z-CHCSSE-9 on its way. Such delay will be somewhat remedied once the second bridge over Lake Pend Oreille is placed in service, but the territory beyond Sandpoint and up around the horn via Bonners Ferry is mostly single track, with several sidings that are still unbonded and/or have road crossings through them. That translates into excrutiatingly slow meets.

East of Bonners Ferry, there's the Kootenai River Canyon with its roughly 18 miles of 30mph max for freights. Barrying any meets against them, an eastbound fleet that somehow manages to reach the canyon on generous headways will eventually compress into tighter headways because the first train entering the canyon at 30 has the next train still closing in behind it at 45-55 until it too reaches the canyon, and so on.

That all being said, the dispatcher can somewhat balance the approach of WBs and EBs to the tunnel by how he or she executes meets on either side. But under the reality of circumstances, if there's a flow of traffic headed predominantly one way, a stack-up-and-wait cycle is pretty much unavoidable.

To say nothing of the many unexpected factors that can slow or stop the lead train in a fleet such as losing air, locomotive failure, signal malfunction, striking an animal (or automobile), etc. 

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Posted by Overmod on Wednesday, January 20, 2021 9:26 AM

Bruce Kelly
So, even if the best laid plans of dispatchers and crew callers could manage to somehow send a fleet of eastbounds out of Hauser on generous 30-minute headways, they could easily stack up behind each other at East Algoma (the current east end of two main tracks on the Funnel) if there's a fleet of WBs approaching Sandoint off both the Hi Line and MRL, or just a single Z-CHCSSE-9 on its way.

I guess it doesn't matter how many times someone tries to mention PSR; it'll just be 'assumed away' by invoking problems that proper PSR, in a world with CBTC, just wouldn't have.  I don't say this to question the experience or knowledge of those who know the territory, just that the examples provided happen to be addressable with technical methods.

With CBTC those 'three eastbounds' depart and are operated with the safe stopping distance, varied with speed, between them.  There is no need, and no purpose, for 'generous thirty-minute headways'.  Then they reach East Algoma to find ... what? A surprise?  Westbounds out of nowhere, or a Z train someone forgot to mention?  And the difference between CBTC separation at 30mph vs. that for 45-55?  Calculable, and not showstoppingly different.  Translate it into the difference, in seconds, that that space takes to pass...

What becomes of greater potential interest is, if the formal restriction against close, if not faster, operation through the tunnel is relaxed, and we were to 'prioritize' achieving closer spacing through the tunnel, how that changes scheduling and priority at other points on the railroad in conducting PSR.  Even if the effort is made to produce 'blocks' of fleeted traffic across the section of line containing the tunnel at discrete times of day, the greater throughput might be significant.

I thought through the details of an addition to track machinery that would spot, prepare, form, and test proper nested bonds on the field side of siding rail in a semiautomated manner, probably requiring no more than a few hours to rectify the bond issue end-to-end.  The integrity can then be confirmed at regular intervals, including the electrical and visual observation of the bonds to determine if any one is deteriorating unduly.  (Of course, the issue of the grade crossings is a more serious one, with no particularly easy technical, or even political, answers.)

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Posted by blue streak 1 on Wednesday, January 20, 2021 10:31 PM

I have to wonder if Flathead tunnel was built with the much easier grade based on what the RR had discovered was limiting Cascade?  Not being familar with the topography around Cascade would it have been possible to build it with an easier grade?  It might have been built with the  original thought that it would always be electrified ?

"IF" That was the original design thought then that might be the engineering mistake !

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Posted by timz on Thursday, January 21, 2021 10:30 AM

Probably there was no need for a steeper Flathead tunnel.

No doubt Cascade's builders assumed it would always be electrified.

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Posted by Overmod on Thursday, January 21, 2021 10:41 AM

timz
Probably there was no need for a steeper Flathead tunnel.

IIRC there was an article in Trains about it at the time it was in construction, which indicated it (and its route) were surveyed and built to produce the minimum gradient.

Reading the contemporary accounts of Cascade's construction, I got the clear impression it was the 'lowest grade' solution that made overall sense.  There was an extensive line improvement (Chumstick?) conducted with the 'fill material' from the tunnel construction that was at least as important a route improvement.  

No doubt Cascade's builders assumed it would always be electrified.

In the late '20s there was nothing on the horizon that would permit anything but electrified operation.  On the other hand, there was nothing in safe regenerative braking, even in that age before dramatic fade from overheating composition brakeshoes, that would allow full reliance on electrification for control of downgrade speed, as Erik indicated, and I think any alternative to the assumption of continued electrification would only increase 'braked' time more.

The sobering thing to me is that it's been nearly a half-century since the dual-mode-lite work was first undertaken, and no railroad has even considered it for this kind of situation.  That puts teeth in what the 'practical men' have been saying in this thread, and it means that very great care in prospective design needs to be done to make the idea practical in future.

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Posted by BaltACD on Thursday, January 21, 2021 11:17 AM

Lets remember one thing about such engineering projects as the Cascade Tunnel - they were laid out by men on the ground without the benefit (or curse) of any of the modern engineering tools (GPS, Google Earth and a host of other tools I can't comprehend).

The original lines for the route having be determined by men on horseback with their transits etc.

Never too old to have a happy childhood!

              

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Posted by Overmod on Thursday, January 21, 2021 11:34 AM

BaltACD
Lets remember one thing about such engineering projects as the Cascade Tunnel - they were laid out by men on the ground without the benefit (or curse) of any of the modern engineering tools (GPS, Google Earth and a host of other tools I can't comprehend).

That stuff's just a convenience for real civil engineers and surveyors.  The late '20s might as well be today as far as the optical and geometric accuracy that could be achieved with contemporary transits or theodolites.  In fact I believe the 'shooting' accuracy of many earlier tunnels turns out to be well within 'construction tolerances' even when building in stages.  People just took more time and more care with their calculations, and perhaps estimated and checked their work more carefully than today.

MC is probably the best authority on this here.  There was no lack of skill, and probably experience, laying out either the original or the revised Cascade Tunnel.  As I recall there was at least one lower-grade alternative (which one of the surveyors favored) but management rejected it.  And it's the men who manage money that manage the men who manage men who manage the men who manage things.

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Posted by VerMontanan on Friday, January 22, 2021 11:04 PM

Bruce Kelly

MidlandMike, I've seen past figures from BNSF that say the practical capacity of Flathead Tunnel is something like 44 trains per day. It would not surprise me if there have been occasions when the tunnel has handled more than that. 

Indeed, I am aware of several times when 54 trains have been operated through the tunnel in 24 hours in the mid-2010s.  In the summer of 2009 during the Mullan Tunnel collapse (and most MRL traffic was routed through Flathead Tunnel), 45 to 50 trains daily was commonplace.  One day in August 2009, BNSF dispatched 17 unit trains (coal and grain) west from Shelby in a 24-hour period from 0001 to 2359.  During that same period, the westbound Empire Builder that operated arrived in Seattle on time the following day.  While this is a better testimony to the superior operating characteristics of Marias Pass, it does show that, in the whole scope of things, Flathead Tunnel is just not that big of a headache.  Grade is a more limiting factor, as was discussed earlier in this thread with regard to Cascade Tunnel.  But the approach to Flathead is only 1% with a track speed through the tunnel of 50 MPH, in stark contrast to grades and track speeds on the UP over the Blue Mountains or westbound on MRL on Mullan Pass.  Fifty trains a day - especially with many being heavy unit trains - doesn't work without a second main track, tunnel or not.  

Mark Meyer

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Posted by MidlandMike on Saturday, January 23, 2021 6:14 PM

VerMontanan
In the summer of 2009 during the Mullan Tunnel collapse (and most MRL traffic was routed through Flathead Tunnel)...

Is the ex-NP route over Homestake(?) Pass still "intact"?  Could it have been reactivated at that time?

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Posted by Erik_Mag on Saturday, January 23, 2021 7:59 PM

From what I've read, Homestake Pass would have taken a lot of work to be put back in service in 2009.

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Posted by VerMontanan on Saturday, January 23, 2021 9:50 PM

MidlandMike

Is the ex-NP route over Homestake(?) Pass still "intact"?  Could it have been reactivated at that time?

No, couldn't've been used in 2009.  Had already been out of service (from Spire Rock to Butte) for 26 years by then.

It is still intact, however.  Of the 122 miles from Logan to Garrison: 50 miles (Logan to Spire Rock) operated by MRL; 20 miles Spire Rock to Butte, still owned by BNSF - rails in place badly deteriorated; 52 miles Butte to Garrison, operated by BNSF (Copper City subdivision).

The route over Homestake Pass was steep (2.2% grades each way), had very short sidings and was the curvature champion of the world.  Not easily revivable or worth reviving.

 

Mark Meyer

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