Heavy cutterhead lifting completed for Łódź high-speed rail tunnel in Poland, excavation expected to start in 2027

en.Wedoany.com Reported - On November 9, the Łódź high-speed rail tunnel project in Poland completed the lifting of a tunnel boring machine cutterhead with a diameter of approximately 14 meters and a weight of about 430 tonnes, lowering it into the Retkinia launch shaft. The cutterhead is the heaviest single component of the complete tunnel boring machine. Assembly of the full machine and equipment testing will continue, and tunnel excavation is planned to start in spring 2027. Once completed, the approximately 4.6-kilometer tunnel will connect Retkinia and Łódź Fabryczna station and form an important part of Poland's "Y"-shaped high-speed rail line.

The lifting operation used a dedicated gantry crane with a rated lifting capacity of 450 tonnes. The lowering and positioning of the cutterhead required high installation precision, with permissible deviation controlled within ±5 millimeters. At present, some trailers, the shield body, the main drive unit and the cutterhead support structure of the tunnel boring machine have been delivered successively and partially assembled in the underground shaft. The complete equipment is about 130 meters long and has a total weight of about 4,000 tonnes. It adopts variable density shield technology and can adapt to complex urban underground geological conditions. The tunnel project is being implemented by PORR, a contractor under Poland's Pol Group, and the related railway signaling system is being designed and built by Alstom.

The tunnel is about 4.6 kilometers long and about 14 meters in diameter. It will be excavated in a single pass by one tunnel boring machine and will accommodate double-track railway upon completion. The tunnel route runs from the Retkinia launch shaft in western Łódź to Łódź Fabryczna station, and five auxiliary shafts will also be built along the route for functions such as emergency evacuation. The designed maximum operating speed of trains in the tunnel is 160 km/h. Main construction is scheduled to be completed in 2029, after which system testing and infrastructure certification will be carried out.

During shield tunneling, the project will use pipeline transport to convey excavated soil to a ground separation and treatment facility. The project team expects that, compared with conventional off-site soil haulage, this solution can reduce about 80,000 heavy truck trips and lower the impact on urban road traffic during construction. At the same time, the contractor will install geodetic monitoring systems on buildings along the tunnel route to continuously monitor the condition of building structures and surface changes.

The Łódź Cultural Center is one of the key protected buildings along the route. The tunnel will pass beneath the building, and the nearby area also involves construction of the shield receiving shaft and track turnout shaft. To protect existing buildings and foundations, the project has installed about 1,400 micropiles and high-pressure jet grouting reinforcement piles beneath and around the building. The main foundation treatment work has been completed and is now in the inspection and acceptance stage.