A major milestone has been reached at the construction site of the high-speed rail tunnel in Łódź. The launch chamber at Retkinia now has a completed cradle for the TBM shield, and first parts of the tunnel boring machine have been delivered and are being assembled.
The cradle is a specially shaped, semi-circular concrete foundation that will support the shield of the Tunnel Boring Machine. Its task is to keep the machine in the correct position and allow it to be slid accurately into the launch opening in the chamber wall. According to CPK, the precision of this element is crucial for the start of tunnelling, because even a small geometric deviation could affect the machine’s trajectory in the first phase of tunnel construction.
The structure was completed in nearly three weeks, with work carried out continuously 24 hours a day, seven days a week. Four specialist tunnelling teams were responsible for the task, bringing together experts from Poland, Austria, Germany, Slovakia, Romania, Croatia and Italy.
Precision work in the launch chamber
CPK said the cradle required high accuracy and constant technological supervision. The element had to match the parameters of the TBM shield and the opening prepared in the wall of the chamber. This is why the work was organised as a round-the-clock operation, with several teams rotating on site.
While the cradle was being built, the first components of the boring machine were delivered to the investment site and lowered into the chamber. They are now being gradually joined into a single structure. After assembly and the necessary technical tests, the TBM will be pushed into the prepared launch opening.
Start of tunnelling scheduled for 2027
CPK has confirmed that the actual drilling will begin in the first quarter of 2027. This date comes from the timetable prepared by PORR, the general contractor for the tunnel. According to the company, 2027 will be the year when work starts on one of the most important sections of underground railway infrastructure in Poland.
The launch chamber in Łódź is being adapted for the installation of the TBM, and the completed cradle is one of the final major elements needed before drilling starts. Once the machine is installed and tested, the wall opening will allow it to enter the tunnel route.
With the cradle finished and the TBM assembly underway, the high-speed rail project is clearly approaching the phase that will create the actual underground structure. The involvement of teams from several European countries underlines the scale and technical complexity of the investment.
Źródło: WNP.PL, Fot. CPK
