The first TBM for Metro Line 4 is in Athens – The course it will follow underground

In Athens, the first of the two TBMs that will open the tunnel of the new line 4 has arrived. According to information, all the pieces of the machine have arrived at the port of Piraeus and in the next few days, in consultation with Attiko Metro, their transport to the KATECHAKI well will begin with special trucks.

The space there is ready to receive the heavy machine. Then it will begin its assembly, which is expected to last until the holidays. The aim of the consortium is to start the journey of the metropolitan at the beginning of the year, ideally in January. Here we are on schedule, and in his statements ahead of time, the Minister of Infrastructure, Kostas Karamanlis, had stated about starting the opening at the beginning of 2023.

The second TBM is in the factory in Germany, fully assembled and in the process of maintenance. The key point for it to be disassembled and to start its journey to the port of Piraeus is to assign the machine’s reception area at the construction site of ALSOS VEIKOU to the construction consortium.

According to well-informed sources this will be done in October. Excavations will then need to be started to enable the transport of the dismantled machine and then the assembly and start-up of the second machine as well. The start of the journey of the second metropolitan is placed in Spring.

The …quiet TBM

The TBMs were manufactured and assembled at the Herrenknecht AG factory in Germany.

They are 100 meters long and over 9 meters in diameter. Their weight is 1,500 tons per machine and they have the most modern technology to offer.

The most important thing for Athens is that the two machines have specially configured machines in such a way as to ensure for the first time zero disturbance during the opening of the tunnel of the new line 4.

It is worth noting that after 20 years, new TBMs are coming to the country’s Metro projects. Used TBMs were used in the extensions of the Athens Metro and also in the construction of the Thessaloniki Metro.

The factors for tunneling

Tunneling speed usually depends on two main factors. The first is the type of subsoil it will encounter. Usually TBMs have difficulty with loose, cavernous or particularly hard terrain. The second factor is the speed of building the stations.

Unlike previous metro projects, the machine will reportedly be able to pass through each station without ensuring that the station’s trench is complete, that is, excavations have reached the bottom of the station. This means that in every breakthrough the journey will continue seamlessly. According to the same sources, the subway lines are expected to find ready stations in the center of the city, which will also be the last to be opened.

It is worth noting that we will have a Metro tunnel opened by TBM after years. It was in 2017 when the subway train on the extension to Piraeus arrived at the Dimotiko Theatro and a little later at the station. Six years later the first subway will begin its underground journey to the eastern suburbs and eventually the center.

The GOUDI station will be the first that it will meet on its way and then it will pass through ZOGRAFOU and ILISSIA. These two stations are located in highly populated areas. Accordingly, the second subway will start from the station to the ALSOS VEIKOU terminal and will proceed through GALATSI and ELIKONOS stations.

According to the programming of Attiko Metro, the meeting and exit point of the two machines is at EVANGELISMOS. To get there, the first TBM will also need to pass through PANEPISTIMOUPOLI, KESARIANI and reach the center. The second will continue their journey passing through the stations KYPSELI, DIKASTIRIA, ALEXANDRAS, EXARCHIA, AKADEMIA, KOLONAKI.

The two machines will meet up at the Evangelismos construction site from where they will be dismantled and left to be reused again in another project.

Preliminary work

At this time, preliminary work continues at the stations of line 4 carried out by ERETVO. Work site occupation has taken place in 14 of the 15 stations and the occupation of the construction site in Evangelismos remains. The bypass of utility networks should then proceed.

Archaeological works are carried out at the stations: A.VEIKOU, GALATSI, ELIKONOS, KYPSELI, DIKASTIRIA, ACADIMIA, KOLONAKI, KESARIANI, PANEPISTIMOUPOLI.At each station that is completed, the process will be handed over to the construction consortium that is the AVAX-GHELLA-ALSTOM scheme to proceed with the main projects.Line 4 stations will all be lateral, with safety doors on the platforms, with automatic wires that will move and be controlled through a control center. The platforms with a length of 80 meters will be shorter than the lines 2 and 3 which are 110 meters, but the routes will be able to be up to every 90 seconds due to the technology they have.