Western Railroad Discussion > UP Salt Lake cause way

I'm hearing reports of Sags on the SP cause way across the salt lake on the UP..., UP has an inspection crew looking over what has to be done, any body heard any thing about this???

Havent heard anything recently,but there has been plenty of discussion and pics here over the years.I understand the problems out there are pretty much a continuing process.
Regards,dK

Think this causeway is on its last legs

There is a very strong buoyancy effect in the Great Salt Lake, because the specific gravity of the salt water is much more than 1.0, maybe 1.24 (but if anyone knows exactly, please post your number). This means that the effective weight of that part of the fill which is below water level is relatively light compared to the part out of the water.

The bottom of the lake is a very soft assortment of uncompacted silt, salt crystals, and layers of salt crust from times when the lake completely evaporated. This means that it can barely support the fill when it sticks a few feet out of the water. Now that the lake is evaporating the fill is higher by many feet it is also placing a heavier burden on the lake bottom than at any time since the fill was raised in the late 1980s. It is to be expected that the weakest parts are settling down into the ooze at the bottom.

Three history lessons:
When the lake was built some sections collapsed under the weight of the new rock fill. These sections were stabilized by building "counterbalance" reefs about 150 feet out in the lake that were brought up to the water level. This gave a resisting force to the classic "rotational slide" failure observed then. We were maintaining the counterbalances by adding rock lost to wave action in the 1970s.

When the SP undertook the massive repair and raising of the fill in the 1980s, the late Richard Mahon commented that it would some day stick out of the water like a sore thumb, the old heads around the lake knew then that the cycles of the lake go up and down.

In about 1997 Bill Wimmer, Chief Engineer of the UP, shared with me some photos of severe settlement "sags" he was working on (he knew I had worked on the fill decades ago). This was when we were on one of his periodic inspection trips through Southern California, I was invited on the trip as his train ran over Metrolink track on two routes.

railstiesballast Wrote:
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> There is a very strong buoyancy effect in the
> Great Salt Lake, because the specific gravity of
> the salt water is much more than 1.0, maybe 1.24
> (but if anyone knows exactly, please post your
> number).

The number I always hear thrown around is a specific gravity of 1.17

Does anyone know how far down you would need to go in order to hit bedrock? The Great Salt Lake truly seems bottomless in many ways.

Posted from iPhone

Years ago ESPEE had the same problem on part of the NWP.

Frontrunner Wrote:
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> Years ago ESPEE had the same problem on part of
> the NWP.
or was it the Cal-P (where it crosses the Suisun Marsh)?

Steve Donaldson
Pacific Grove, CA

Yep, when they first built across Suisun Marsh they had the same problem. They built up the shoulders. I think it was in Signor's Western Division book that I read about that.

> -----
> > Years ago ESPEE had the same problem on part of
> > the NWP.
> or was it the Cal-P (where it crosses the Suisun
> Marsh)?

WAF Wrote:
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> Think this causeway is on its last legs

When did it get its "first legs". What ever they are?

stampedej Wrote:
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> Does anyone know how far down you would need to go
> in order to hit bedrock? The Great Salt Lake truly
> seems bottomless in many ways.
>
> Posted from iPhone

In 1953 IE and and in 1983 Haley and Aldrich measured the depth of the unstable blue clay layer in the center of the lake and out of the salt layers to to extend to a depth over 1200 ft.

1200 feet! Yikes!

Posted from iPhone

JLY Wrote:
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> WAF Wrote:
> --------------------------------------------------
> -----
> > Think this causeway is on its last legs
>
> When did it get its "first legs". What ever they
> are?


1959 when it was built.

WAF Wrote:
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> JLY Wrote:
> --------------------------------------------------
> -----
> > WAF Wrote:
> >
> --------------------------------------------------
>
> > -----
> > > Think this causeway is on its last legs
> >
> > When did it get its "first legs". What ever
> they
> > are?
>
>
> 1959 when it was built.

Settlement "legs" were not the worst problems circa 1965-1988. It was wave action due to the unprecedented raise in the lake level.
The UP Engineering Dept. has confidence in its ability to maintain the causeway.

I just had a conversation with Jim Mahon (The Bear) about this subject. His opinion is that the Lake will continue to be an ongoing maintenance nightmare. He has suggested that a new line be built from a point just west of Wendover, up the valley just west of Pilot Peak and around the north end of the Toano Range to a connection with the SP main just east of Cobre. This line would provide several advantages. First, it would eliminate the operating pain of Silverzone pass and the run down to Clark Tunnel and then back up to Wells. Second, it would eliminate the GSL causeway. Third, it could all easily be built for high speed operation. It looks reasonable to me as I look at the topol maps. What do you think?

Sure, for 500 million dollars. What a deal. All great ideas of detouring around the lake have been discussed and rejected by the UP

Why not jus rebuild the old CP line. Mahon's idea put many extra miles into play and runs trains through SLC which means you still have to get back to Ogden



Edited 3 time(s). Last edit at 06/15/14 20:09 by WAF.

donnerpass Wrote:
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> I just had a conversation with Jim Mahon (The
> Bear) about this subject. His opinion is that the
> Lake will continue to be an ongoing maintenance
> nightmare. He has suggested that a new line be
> built from a point just west of Wendover, up the
> valley just west of Pilot Peak and around the
> north end of the Toano Range to a connection with
> the SP main just east of Cobre. This line would
> provide several advantages. First, it would
> eliminate the operating pain of Silverzone pass
> and the run down to Clark Tunnel and then back up
> to Wells. Second, it would eliminate the GSL
> causeway. Third, it could all easily be built for
> high speed operation. It looks reasonable to me
> as I look at the topol maps. What do you think?

If this had of been feasible it would have been done about the same time as the Lucin cutoff was considered.
I know personally this and about a half of a dozen other detour routes including a connection from Lakeside to Rowley on the old WP were proposed and studied in 1983 including rebuilding the old CP route and the decision to keep the causeway was considered the best plan.
This plan must have had some merit as the causeway is still in service.
I don't remember the "Bear" when he was out there in those days coming up with any bold schemes to solve the problems on the Causeway.

I wonder what the comparisons are, cost-wise?

Average yearly cost of maintaining the causeway: ???
Average yearly cost of running via the ex-WP line instead, fuel & time cost-wise?

Projected cost of rebuilding / operating the old CP line?
Projected cost of additional fuel, wear & tear, and time using a rebuilt CP line vs. causeway maintenance?

Sometimes, it seems decisions are not made on pure dollar cost basis. Ease of use must come into play. It's like accepting a pick-up over a car, because the truck is useful in other ways, even though it's costing you alot more to keep it. It seems the same with this causeway. Ogden is the issue. The more I read about it and all the geological engineering challenges it presents, the more it amazes me that UP keeps it.

I saw some show on TV where they mentioned that, as long as wood pilings remain submerged in water, they are not subject to rot or deterioration. It's when they are partially submerged that the damage takes place at the point where the wave action comes in contact with the wood.

Was there ever a proposal to protect the wood pilings on the trestle with concrete caps? While expensive initially, such a plan might have been the great "cure-all" to this problem.

The money that was spent on the earthen fill would have paid for an awful lot of concrete caps.

Of course, one drawback of the trestle was that you couldn't feasibly raise it when the lake level rose radically.