Would by any chance anyone know anything about progress on the work to upgrade the North-South railway connections in eastern Greece? I am particularly intrigued by developments (or non-developments...) in the tunnelling at Kallidromo. The planned 9 kilometers of base tunnel will, once completed, give a tremendous shot in the arm to the intercity trains Athens-Thessalia-Macedonia. I know that the work was discontinued in 2002 amid geological mishaps, then apparently restarted four years later, but since then the internet sites I usually consult have lost track of the project.

Does any Greek speaker of this forum know more about this or, as the case may be, other undertakings to speed up the eastern line?

Right now, it is estimated to be completed in 2015. When it is finished, it will shorten the travel from Athens To Thessaloniki by 25 minutes. However, the area has proved to be a geological nightmare, and it may be delayed even more.It is the larger tunnel built in Greece right now, one of the larger built in Europe and one of the 3 most techically challenging worldwide.

There is this site, http://www.ergotaxiaka.gr/article.php?ID=76 , where you can find information about these projects, but it is in Greek. Perhaps using the Google translation might help you.

^^ Many thanks for the information, Ares. (Is this bellicose nick your real name, BTW? :)) I tried to translate the Greek article to English and it's quite interesting. I wish I knew exactly when it was written. It looks like it may have been in 2007 when they found a new contractor to thake the work forward: there are references to 2 x 1.5 km having been bored on each side of the tunnel so "now we only have to do the remaining 6 km". That sounds like they've decided what to do, but have not yet started doing it.

If I understand the part about Kallidromo correctly, their main problem was that they got into some form of "tixotropic" layers - i.e. soil that seems solid enough but, given a sudden blow (or drill vibrations...), may release most of its "grid water" and turn into liquid mud. Poor bastards. This makes (again, if I've understood the matter correctly) the whole operations sooOOO much more expensive. The only way, as far as I know, to overcome this problem is through an integrated drill/tunneling process where the drill head acts as a "submarine" and the tunnel is created directly in its wake, like a giant hose keeping the water out and the roof up. :ohno:

One last question: when you say the project is going to shave 25 minutes off the time between Athens and Thessaloniki, do you mean Kallidromo alone? The article you provided speaks of three separate undertakings.

Ares_K = Ares Konstantinidis, which is the name of a Greek architect whose book i happened to read just before joining the forum. Not related to my real name or the God of war :)

All three projects will shave off 55 minutes. The 106 kilometers from Tithorea to Domokos , where there is a single line over the mountains is the one that keeps the trains from achieving maximum speed and keeps the Athens-Thessaloniki down to 4 hours and 15 minutes right now. It will go down to 3 hours and 20 minutes after 2015 , hopefully, when all three projects are finished.

^^ Thanks again. I sniffed around a bit and found the following information (it's only the blurp of an article - and in German).
http://www.baufachinformation.de/zeitschriftenartikel.jsp?z=06079012456.

It looks like my little hunch was right: they started making the tunnel in the old fashioned way, carving out the rock with heavy construction machines, stone drills, etc. and spray-cementing the walls as they went along. As they came into unexpectedly harsh conditions - water seeping in, the pressure on the ceiling mounting critically - they had to stop for fear the whole mountain would come down and crush them. Enter, a huge drilling machine, inured against pressure and with the operators sitting inside (hence not exposing themselves), which makes the tunnel lining from shells of hardend concrete shells as it goes along.

The latter solution is, in my amateur opinion, a good one. It's also the one used by the Swiss for their Gotthardt project and Spaniards for most of their (many) tunnels-in-progress. I have to say, though, that someone in some planning department may have been a bit over-optimistic in their first approach. Did they really assume that they could chip away at 9 km of deep rock without the roof, at any point, threatening to fall in? :ohno:

The Kallidromo twin tunnels are advancing with 1 - 1,5 m per day from each side due to bad conditions (serpentine schists). Last February (2010) there were remaining about 1600m to be excavated so that both worksites meet. That means that the excavations will finish in 2012. The excavation of the invert (the bottom part of the tunnel so that the final cross section looks like a pipe) and construction of the final lining of the tunnel follows a few meters behind the excavation of the upper part (arch) in order to avoid convergence and damages or even the collapse of the arch.

Similar or slightly better excavation rates apply to the Othrys main twin tunnels (2 x 7km long) north of Lianokladi (mainline station that serves Lamia).

The tracklaying and electrification works have not been tendered yet but are due in early 2011 which means that an opening date in 2014 for the whole section Tithorea - Domokos is possible.

The problem for all projects in Greece is that many contractors have not received any or only little payments from the state since last summer thus they are working in tunnels only in two or even one shift (instead of working round the clock) and they have completely closed some other worksites.

I travel often by train. I can see a slow but stable progress between Domokos and Lianokladi part where you can clearly see the bridges rising.