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Post by kerouac2 on Apr 28, 2018 12:12:27 GMT
Yesterday, I was able to participate in the very last visit of the tunneling machine for one of the metro lines being extended. Next week, it will break through to its sister tunnel north of Paris and will be disassembled. Of course, there will be more visits in the future, because this particular visit was on line 14 of the metro. There will be another major section of line 14 extended in the south in the coming years, and work on new metro lines 15, 16, 17 and 18 has barely begun, so all of this will go on until 2030 at the very least, by which time there should be even more new projects. I already made a report a few years ago about the extension of metro line 12, which is still not open -- these things take forever -- but the tunneling was already complete and most of the rails were aleady down, so it was a completely different experience.
The rendezvous was at Pont Cardinet in the 17th arrondissement, at a corner of the Martin Luther King park.
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This was quite chic compared to my last visit because there was even a small visitor centre with a model of the beast and other visuals.
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Normally, there were a grand total of 3 visitors (the maximum is 5 for security reasons) but on this final day, another guide was there with her entire family, including a small child (normally you have to be at least 18 to visit).
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The new Pont Cardinet metro station will be extremely useful because a gigantic new neighbourhood is under construction here.
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A construction lift took us down into the hole.
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We began our journey through the tunnel.
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Post by kerouac2 on Apr 28, 2018 12:25:59 GMT
The tunneling machine was much more impressive than I expected. I knew that it was huge -- more than 100 metres long -- but it was actually like being in a submarine. It is completely self-contained with a dry toilet, dining area, etc. It is in operation 24 hours a day with three crews (3 x 8) with no return to the surface during their working time because walking through the tunnels takes too long. Just our little "tourist" visit lasted more than four hours, more than half of the time spent walking. Even in the tunnel before you get there, the noise is pretty deafening because of the huge ventilation duct but also the conveyor belt taking away the debris. Paris is lucky, because it is almost entirely just muddy sand, but every now and then they hit a rocky area. We finally reached the machine and entered it. I was frankly surprised that they allow any visitors at all because the passages through it are very tricky and all sorts of dangerous things are happening most of the time. I hit my hardhat three times on various things, so I now completely understand the importance of wearing a hardhat at all times in places like this. The video will give you a better idea of the inside of the machine. We even entered the control room with the pilot at work. Even though I think we know that these things are extremely complicated, I was astounded at all of the things that you need to check before advancing even one centimetre. Naturally, the computers are telling them everything these days, so it is even more incredible to imagine how they managed to drill some of the tunnels of the past like Mont Blanc or even the Channel tunnel, when the computers were less sophisticated. You may note that the title of my video is not overly explicit because it was vaguely mentioned that private photos were authorised but not for social media. |
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Post by kerouac2 on Apr 28, 2018 12:39:53 GMT
If you have ever read about these incredible machines, you will know that they drill forward but at the same time they install the permanent walls of the tunnel as they progress. You probably noticed the gigantic hydraulic presses to put the sections in place in the video. Each section interlocks like a Lego set and also has rubber seals to prevent any leakage. This particular machine was German made, but the one coming from the other direction is Franco-Chinese. As long as they work properly, who cares? |
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Post by bixaorellana on Apr 28, 2018 12:53:19 GMT
Really interesting and downright awe-inspiring.
Your explanations and pictures are excellent, of course, but I'm going to have to go through this again to try to grasp it better. It is pretty mind-boggling that this is even possible, much less in a way that seems almost sanitized.
Were you all issued with any kind of ear protection?
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Post by questa on Apr 28, 2018 13:33:12 GMT
I love massive engineering projects and infrastructure building. I am so in awe of the guys who start with some sketches and wind up with a giant like this tunnel...even the fact they are working from both ends and will meet accurately in the middle. Great photos K2, just as well you don't get claustrophobia.
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Post by mossie on Apr 28, 2018 15:46:43 GMT
Talking about meeting in the middle. I did a little fantasising. What if they made a slight distance miscalculation, what with one being German and the other Chinese. What a wonderful terrible grinding noise that would make, I have these problems when I listen to our traffic bulletins and they talk about an "accident between Junction 10 and Junction 11", and I imagine all the broken concrete and torn up asphalt that would follow. Daft as a brush, I know.
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Post by kerouac2 on Aug 8, 2020 17:57:15 GMT
This portion of the line is opening in December.
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