For a bridge built about the high-tide line, I would think the more serious issue is the beach sand beig displaced south by the California current. The sand forming beaches in SoCal comes mainly from sand washed down what are called rivers and creeks along with erosion of the sandstone bluffs. Most of the erosion is caused by waves striking the base of the bluffs.
Having seen several piers survive decades along the coast, I suspect that a beach front trestle would last a decent amount of time if the piers for the trestle were sunk deep enough. I would be a bit more concerned about the effects of salt water on whatever the trestle piers were made of.
York1 MidlandMike The bridge piers would have to be set in stable ground, which might be too deep to reach practically. I understand the need for earthquake-proof piers that makes it more of an issue than bridges in Louisiana. In Louisiana, there really is no bedrock or stable ground for the piers. Most of the building there relies on friction pilings for stability. I don't know how that would work in California.
MidlandMike The bridge piers would have to be set in stable ground, which might be too deep to reach practically.
I understand the need for earthquake-proof piers that makes it more of an issue than bridges in Louisiana.
In Louisiana, there really is no bedrock or stable ground for the piers. Most of the building there relies on friction pilings for stability.
I don't know how that would work in California.
Earthquakes will always be a concern, but the stable ground I was refering to would be below any apparently slipping land due to large scale erosion such as rotational block slipping.
MidlandMikeThe bridge piers would have to be set in stable ground, which might be too deep to reach practically.
York1 John
Gramp Would it work to convert the current ROW to low level bridging where the line is vulnerable? Kind of like NS Lake Pontchartrain bridge. Less costly than tunneling a new route?
Would it work to convert the current ROW to low level bridging where the line is vulnerable? Kind of like NS Lake Pontchartrain bridge. Less costly than tunneling a new route?
The bridge piers would have to be set in stable ground, which might be too deep to reach practically.
A low level bridge may work for the portion of the San Clemente trackage where the high tide line runs up against the rip-rap. The engineering challenge would be building bridge piers that would stand up the salt water and the action of waves. A related challenge is doing this while still running trains - one option is to build the new line about 30' to 40' west of the old line, then tear up the old line and build a bridge for the second track.
The secion in Del Mar is built on top of bluffs, so it would be easier just to build a sea wall along that section if it could get approved b th Coastal Commission.
Financing this consruction would have been easy a year ago as the state was flush with tax revenues - suspect a lot was capital gains on stock sales (Calif doesn't distinguish between short term and long term). Tax revenues have been way down the last two quarters, so state budget surplus is rapidly diminsihing.
Getting approval from the Coastal Commission could be very tricky and I wouldn't be surprised if the permitting process would take 10 years to get final approval.
It's easy to talk about the things that should be done unless those things involve ruining my property or lowering the value of my house.
There's a reason why the residents of Del Mar are called Del Martians...
Putting a tunnel under Del Mar will almost certainly require condemnation of a few homes and possibly some businesses. Having said that, the bypassing of the Surf Line though San Clemente is likely to much more disruptive and expensive.
Secretary Buttigieg was in town a few days and made comments about the need for a bypass, but I didn't see anything specific about federal funds or schedules.
R&TS had a recent article summarizing positions on the rail-relocation issue by 3 people running for office in Del Mar. Might be interesting to read an official transcript about 'devastating' tunnels...
San Juan Cap webcam tonight (Friday) as of midnight: 11:45 PM, NB BNSF manifest with five engines leading.
EDIT: 12:48 AM Saturday, NB BNSF 4 leaders and 56 auto racks. 1:01 AM SB BNSF 3 leaders manifest. Nothing else to daybreak.
In other words, continues to look like business as usual for BNSF.
Continuing with the San Juan Cap webcam, tonight Thursday (10/27/22) at about 10:50 PM PDT, northbound BNSF with three leaders and 66 auto racks, which I guess confirms my suspicions that we had an auto carrier call in the port this week. Then at 11:03, a southbound BNSF manifest, relatively short but with four engines leading. Then, 11:15 PM or so, 2 leaders, 87 auto racks and one DP on the end. That's gonna be fun on the grade crossings from Old Town south to the yard.
Apparently the track issues that have the passenger folks all excited are not stopping BNSF, though they may have slow orders for a little while on the south end of San Clemente. I wonder if another rip-rap train will come through before dawn again.
Edit: On further review, another southbound BNSF at 11:53 PM with two units on the head end and 40 auto racks. Nothing more, at least up to 5:50 AM. No rip-rap train this morning.
San Juan Cap Monday Nite (10/24/22) railcam, 10:45 or so PM PDT, BNSF Southbound manifest, 4 leaders, one DP on the rear. Nice mix of what I would call normal SD bound cars.
Edit: Tuesday night (10/25/22) 10:36 PM PDT, BNSF 2 units leading 55 auto racks southbound.
Edit again: Wednesday Night (10/26/22) 11:43 PM PDT, BNSF southbound, 2 units leading 66 auto racks. Thursday morning (10/27/22) 4:15 AM PDT, BNSF southbound, 2 leading, 26 low gons loaded with rip-rap followed by 2 dp on the tail. Guessing an auto carrier unloading in SD.
Erik_MagAnother unresolved issue in the Climate/CO2 debate is how does a pulse of CO2 last in the Atmosphere/Oceans/Biosphere before it is geologically sequestered? My understanding is that more carbon is in the form of limestone than in all of the potential fossil fuels. ...
Yes, there is much more limestone and other carbonate rocks that fossil fules. However the major component of limestone (and a lot of sea shells) is CaCO3. Of course it needs calcium but its formation depends on the partial pressure of CO2 and temperature. Increasing CO2 causes formation of carbonic acid H2CO3 in seawater which disolves limestone and reefs.
One issue with the correlation between CO2 and isotope (e.g 18O/16O) temperature reconstruction is whether the change in temperature drives the CO2 or the change in CO2 drives the temperature. Based on high resoluction radiative heat transfer modeling (which ignores convective and phase change heat transfer) indicating a 2C increase for doubling CO2, I would think that the past correlations are mainly due to CO2 following the temperature with a bit of positive feedback from the CO2.
Another unresolved issue in the Climate/CO2 debate is how does a pulse of CO2 last in the Atmosphere/Oceans/Biosphere before it is geologically sequestered? My understanding is that more carbon is in the form of limestone than in all of the potential fossil fuels. Based on 14C measurements after the 1952 - 1963 run of atmospheric thermonuclear tests, the half-life of a CO2 molecule inthe atmosphere is on the order of 15 years (half-life to complete sequestration is probably longer than that).
Getting back to San Clemente: I don't recall seeing anything stating that this part of coastal California having much of an elevation change due to plate tectonics. This implies that relative sea level rise has been on the order of 2 - 3mm per year and there hasn't been much of a change in that rate over the last century.
BaltACD I doubt humans and their activities including fossil fuel use are helping stem the changes to a warmer climate for the thrid rock from the Sun. ...
Carbon isotope studies of the atmosphere show that the increase CO2 is from human activity.
BaltACDWhile we can learn a lot from core samples of both ground and ice, it is not as definitive as being there, which of course was impossible 10K, 20K, 50K years ago. ...
The CO2 concentration data from those core samples corresponds to isotope temperature modeling, and follow the ice ages themselves, all of which backs up the CO2 data despite no one being there back then to record it.
Thursday night (10/20), 11:05 PM, a northbound Amtrak trainset came through the San Juan Cap station, not stopping, stepping pretty good. 11:20 PM, BNSF train headed by 2 GEs pulling 67 auto racks came through southbound.
tree68I asked about sea level rise vs land mass subsidement because we might be able to do something about the climate (although our limited recorded history of the climate begs the question of whether this is completely man-made or just a natural cycle). OTOH, there isn't anything we can do about the land mass sinking...
The Earth's surface has vacilated between tropical forests world wide and snowball earth on multiple occasions without the assistance of human beings. I doubt humans and their activities including fossil fuel use are helping stem the changes to a warmer climate for the thrid rock from the Sun. Truthfully my personal feelings is that the Earth is on its swing to a tropical enviornment no matter what actions humans take; that being said we still must take whatever actions that we can devise to slow down, if not reverse, the trends to a warmer Earth.
Weather records have only been in existence for in the neighborhood of 300 years +-. While we can learn a lot from core samples of both ground and ice, it is not as definitive as being there, which of course was impossible 10K, 20K, 50K years ago. Our record keeping is seriously deficent, for the entirety of the Earth's existence. My information is that the Earth has been in existence for 4.5 BILLION trips around the Sun; humanoids have existed for about 100K of those trips and we have 'data' for roughly 300 of those trips.
Never too old to have a happy childhood!
I asked about sea level rise vs land mass subsidement because we might be able to do something about the climate (although our limited recorded history of the climate begs the question of whether this is completely man-made or just a natural cycle). OTOH, there isn't anything we can do about the land mass sinking...
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
adkrr64 What was the previcted rise in sea levels made 30 years ago, and how accurate did they ultimately turn out to be?
What was the previcted rise in sea levels made 30 years ago, and how accurate did they ultimately turn out to be?
Since 1992, the global average sea level has risen more than 10cm, NASA says. Over the last 30 years, human-caused sea level rise is 10 times that of natural sea level rise.
The 24 October 1983 report Projecting Future Sea Level Rise: Methodology, Estimates to the Year 2100 , 2nd edition, predicted (mid-range scenario, see table 4.1 on page 39):
by 2000:
8.8-13.2 cm
by 2025:
26.2-39.3 cm So in summary, all the scenarios resulted in predictions of sea level rise of well below 1 meter by the present (2018) time. Actual rise has been slightly below the lowest of the scenarios.
26.2-39.3 cm
So in summary, all the scenarios resulted in predictions of sea level rise of well below 1 meter by the present (2018) time. Actual rise has been slightly below the lowest of the scenarios.
Overmod tree68 Is the sea rising, or is the land subsiding? Yes. It's hard to get a straight answer out of exactly how much MSL is supposed to increase this century. The last "real" estimate I saw go by was 4/100" but this obviously would vary if significant ice-cap melting were to 'tip'. In my opinion this would be dwarfed by the wave heights generated in the more severe storms expected. All the present problems appear to be a combination of relative instability of the track structure and pounding of waves from a storm. That is a very different thing from 'climate change' -- but one suspects that journalism-for-profit will not miss the opportunity to blame this directly on some postmodern version of AGW.
tree68 Is the sea rising, or is the land subsiding?
Yes.
It's hard to get a straight answer out of exactly how much MSL is supposed to increase this century. The last "real" estimate I saw go by was 4/100" but this obviously would vary if significant ice-cap melting were to 'tip'. In my opinion this would be dwarfed by the wave heights generated in the more severe storms expected.
All the present problems appear to be a combination of relative instability of the track structure and pounding of waves from a storm. That is a very different thing from 'climate change' -- but one suspects that journalism-for-profit will not miss the opportunity to blame this directly on some postmodern version of AGW.
According to NOAA, sea level along the U.S. coastline is projected to rise, on average, 10 - 12 inches (0.25 - 0.30 meters) in the next 30 years (2020 - 2050), which will be as much as the rise measured over the last 100 years (1920 - 2020).
Is BNSF using light weight locos for their operations by this problem?
tree68Is the sea rising, or is the land subsiding?
SD60MAC9500You'd need to build OHL that clears Plate H.
Overmod This gives free and safe access anywhere under the elevated structure at any hour, allow full 'return to nature' of most of the current ROW, minimize 'train noise' and other impacts, facilitate future dual-mode-lite electrification adoption... etc.
This gives free and safe access anywhere under the elevated structure at any hour, allow full 'return to nature' of most of the current ROW, minimize 'train noise' and other impacts, facilitate future dual-mode-lite electrification adoption... etc.
You'd need to build OHL that clears Plate H. As San Diego is still a considerable import/export port for auto's. I'd reccommend to save the cost use Fuel Cell Multiple Units.
It's one thing to fill in a washout. It's quite another thing to stabilize a moving bluff in a seismically active zone.
ChuckCobleigh Just wonderin’ how long an actual railroad company would take to do the job.
Just wonderin’ how long an actual railroad company would take to do the job.
CN rebuilt/filled in a large trestle in about three weeks after it burned down.
https://www.cbc.ca/news/canada/edmonton/mayerthorpe-s-cn-trestle-bridge-rebuilt-after-major-fire-1.3586555
Another burnt bridge was just filled in and reopened in days.
https://www.trains.com/trn/bridge-fire-halts-cn-service-on-northern-alberta-route/
CP took about 10 days to reopen their mainline through the Fraser canyon after the major flood damage last November. CN was hit worse and took about 20 days before our line reopened for good (a second storm washed away one of the fills right after it had been finished).
Greetings from Alberta
-an Articulate Malcontent
ChuckCobleighToday's SD Union-Tribune:Passenger service between San Diego and Orange counties could remain suspended through end of the year https://www.sandiegouniontribune.com/news/transportation/story/2022-10-18/rail-repairs-will-take-longer-than-expected I saw a BNSF train southbound with a bunch of gons loaded with large rip-rap rock on the San Juan Capistrano webcam several days ago. Just wonderin’ how long an actual railroad company would take to do the job.
https://www.sandiegouniontribune.com/news/transportation/story/2022-10-18/rail-repairs-will-take-longer-than-expected
I saw a BNSF train southbound with a bunch of gons loaded with large rip-rap rock on the San Juan Capistrano webcam several days ago.
Remember, Hurricane Katrina flat out DESTROYED CSX's NO&M Subdivision between New Orleans & Mobile at the start of September. CSX marshalled all the contractors they could find to rebuild the line, from the ground up and install a new signal system. NO&M was placed back in service the first week of March of the following year - roughly five months after the destruction.
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