Western Railroad Discussion > Bulge in Newhall tunnel?

Maybe it has been discussed here before but, if it was, I missed it. Does anyone know anything about the bulge in the south wall of tunnel #25? It looks like it's been there for a while but I've never noticed it before. It's 2900' from the east portal, about 30' long, runs from floor to the begining of the arched ceiling and stands about 10-12 inches proud of the rest of the wall. Is this newer damage or did their concrete forms give when they lined the tunnel?

Can not answer, but this tunnel has been moving ever since the original construction. There are stories of men watching the walls move. It is in a very seismic area, convergence of three mountain ranges. There also is a lot of water in the tunnel cutting, draining all the time.

Posted from iPhone

Don't know why it comes to mind but I seem to remember it gettting worse after the Saugus/Newhall quake many
years ago.

Out

So, are you saying that the bulge was there before the quake?

callum_out Wrote:
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> Don't know why it comes to mind but I seem to
> remember it gettting worse after the
> Saugus/Newhall quake many
> years ago.
>
> Out

Posted from Android

Funny how you can go by something for years and never notice it, I'll have to keep an eye out next time I go that way. Hopefully it's a pre-existing condition.

Reading the history of Tunnel 25 is not for the faint of heart, thanks for reminding us.
After the 1994 earthquake we got FEMA (?) money to tie the bottom of the walls to the rock then pump concrete grout behind the walls to fill the voids where the original wood packing was.  This was done to make the tunnel bore a continuous structure with the natural rock.  I cannot recall whether there was any discussion of a bulge then.
Later we did the same thing to Tunnel 26 on the Coast Line. 
Both tunnels go through basically the same formations, young marine sediments and prone to seeping water continually.  We tried to make sure that we did not seal off the water flows as that would increase hydrostatic pressure.
But a lot could have changed since I left Metrolink in 2006, it is up to the current administration there.
Or maybe E. Musk can slip his magic boring machine up there and make a new one; he makes it sound so easy....
 

I am totally surprised that this tunnel did not cave in after the 1971 Sylmar quake and the 1994 (or 1995) Northridge quake - both of which were classified as "severe" quakes. I remember that both quakes took down the Highway 14 & I-5 interchanges right there at the crux of the canyon pass. To read that this tunnel on the former SP Saugus Line is surviving albeit with the problems and concerns mentioned in this post, is truly amazing.

> Or maybe E. Musk can slip his magic boring machine
> up there and make a new one; he makes it sound so
> easy....
>  

Just as an FYI, the tunnels that Elon Musk is building have a bore 13.5 feet in diameter. A new tunnel dug by a TBM able to allow double stack domestic high cube containers would have to have a bore of what, 30 feet in diameter? That is 5 times the surface face area of the bore than the Elon Musk tunnels. Then you have to take into consideration all the physics of such a sized tunnel.

Bottom line, yes a TBM with a boring face of 13.5 feet in diameter is going to be a hell of a lot faster than that of one with a 30' diameter face.

I have no idea if this is related or not, but there is a section of the 5, directly above the tunnel, that sinks periodically.   Right now, the road sags in the southbound lanes and they seem to patch it every few years.    Now that they are doing construction in the area for the umpteeth time, maybe they will address this again.
There is also a horrible depression on southbound San Fernando Rd., just north of Balboa.   Read somewhere it's fault related, but cannot confirm.   The dip/bump is outrageous though.  Enough to bend a rim, which I almost did last week getting around the 5 construction at 1 am.
 

What familiar landmark/city is in proximity to Newhall Tunnel? 

This tunnel is located on the Antelope Valley line owned by Metrolink between San Fernando and Santa Clarita. The southern end of the tunnel begins close to the intersection of I-5 and CA 14

Thank you Mr. Wizard. Guess you didn't get the sarcasm.

jst3751 Wrote:
-------------------------------------------------------
> > Or maybe E. Musk can slip his magic boring
> machine
> > up there and make a new one; he makes it sound
> so
> > easy....
> >  
>
> Just as an FYI, the tunnels that Elon Musk is
> building have a bore 13.5 feet in diameter. A
> new tunnel dug by a TBM able to allow double stack
> domestic high cube containers would have to have a
> bore of what, 30 feet in diameter? That is 5 times
> the surface face area of the bore than the Elon
> Musk tunnels. Then you have to take into
> consideration all the physics of such a sized
> tunnel.
>
> Bottom line, yes a TBM with a boring face of 13.5
> feet in diameter is going to be a hell of a lot
> faster than that of one with a 30' diameter face.

SP4360 Wrote:
-------------------------------------------------------
> Thank you Mr. Wizard. Guess you didn't get the
> sarcasm.
>
> jst3751 Wrote:
> --------------------------------------------------
> -----
> > > Or maybe E. Musk can slip his magic boring
> > machine
> > > up there and make a new one; he makes it
> sound
> > so
> > > easy....
> > >  
> >
> > Just as an FYI, the tunnels that Elon Musk is
> > building have a bore 13.5 feet in diameter. A
> > new tunnel dug by a TBM able to allow double
> stack
> > domestic high cube containers would have to have
> a
> > bore of what, 30 feet in diameter? That is 5
> times
> > the surface face area of the bore than the Elon
> > Musk tunnels. Then you have to take into
> > consideration all the physics of such a sized
> > tunnel.
> >
> > Bottom line, yes a TBM with a boring face of
> 13.5
> > feet in diameter is going to be a hell of a lot
> > faster than that of one with a 30' diameter
> face.

Guess you didn't get the fact that my post was purely informational and completely non-judgmental?

The Ssylmar quake of Fedruary 9, 1971 was virtually on the spot, but the tunnel survived.  The three level interchange being constructed above iiiiit did not

Built in 1876. Surprised it is still with us.
Photo 1: Early postcard of southern entrence
Photo 2: Tunnel entrence under the FWY bridges
Photo 3: Interior, after construction, by Chinese labor.

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Would the 'Seven Minutes' statement on the sign be the safeeed and time to traverse the tunnel?

James R.(Jim) Baker
Whittier, CA

Talked to another rail this morning who said the bulge had been there his entire career (since 1978) so perhaps it occurred in the Sylmar quake.

Posted from Android