NEWS |


Stockholm Metro service tunnel blasts finish SWEDEN - AItinera has completed the excavation of a service tunnel for the Stockholm Metro Expansion. The final 4m of blasting were achieved in


January, marking completion of the tunnel connecting Hagastaden and Arenastaden as part of the metro network expansion. The contractor said the completion


was of major technical and logistical significance in the urban environment, and paves the way for the start of the subsequent construction phases. The expansion will add 30km of track and


18 stations to Stockholm’s metro network. It is the largest investment in the Swedish capital’s public transport for 50 years and will provide new Blue Line routes from Akalla-Barkarby and Kungsträdgården– Nacka and Söderort; a new Green Line connection from Odenplan-Arenastade; and, construction of the entirely new Yellow Line from Fridhemsplan- Älvsjö. Procurement for the Yellow Line


tunnelling contract is expected to be launched in H1-2026.


Strabag, UEL co-op in R&D UK - The University of East London (UEL) and Strabag UK are collaborating to develop and commercialise a low-carbon grout that could reduce the environmental impact of tunnelling projects. The 26-month project will replace


traditional cement-heavy annulus grout with a sustainable alternative made from repurposed construction waste and biowaste from the sugar industry. The new product is expected to cut embodied carbon by more than 61% compared with conventional formulations. The formulation partially replaces


cement, superplasticisers and retarders with excavated tunnelling material, filter cake from water treatment processes and agricultural by-products. The project is backed by a £216,000


Innovate UK-funded Knowledge Transfer Partnership (KTP), and is supervised by UEL’s Dr Arya Assadi Langroudi, associate professor in geotechnical engineering.


Old rail tunnels widened GERMANY - Construction work was recently completed to enlarge the Cramberg rail tunnel, which was built in the 19th Century. The 732m-long tunnel on the Lahn Valley


Railway, connecting the cities of Koblenz and Wetzlar, is one of two that have been enlarged for Deutsche Bahn. The prior


8 | April 2026


tunnel was 426m-long Fachingen Tunnel, completed in late 2025. The consortium, comprising Porr GmbH


& Co, Feldhaus Bergbau GmbH & Co, and Heinz Schnorpfeil Bau GmbH, used Herrenknecht’s Tunnel Enlargement System (TES) to enlarge the two tunnels to make them both 2m wider. The TES, which is approximately 46m


long, weighs 270 tonnes and has a 12m diameter, enabled DB to keep rail lines operational while the expansion works were underway. Trains are shielded within the TES as works are performed outside.


Yangtze shaft bore launch CHINA - A large-diameter vertical shaft boring machine, manufactured by CREG, has been launched on the Chongtai Yangtze River Tunnel project. The machine, named ‘Qiming’, was


launched at Shaft No. 2, which is a key TBM reception and relaunch chamber for the high-speed railway project. The 14.25km-long project has three


vertical shafts and Shaft No. 2 is located in a floodplain, only 200m from the Yangtze River. CREG said the 24m-diameter machine enables a submerged, fully-automated mechanical vertical shaft boring solution, to a maximum excavation depth of 150m. The shaft boring machine has a dual-


arm structure integrating excavation, muck removal, and guidance functions, along with technologies for posture adjustment, settlement control, and geological sensing. CREG said the machine is adaptable across soft soil, soft rock, cobble layers, and alternating soft and hard rock formations. The milestone launch of the shaft


machine also signals preparations for the relaunch of TBM ‘Linghang’, added CREG.


Mumbai sewer advances INDIA - J Kumar MEPL JV recently achieved a significant breakthrough on the Mumbai Sewer Disposal Project (MSDP) Stage II. TBM tunnelling crews broke through on


Priority Sewer Tunnel 1 (PST-1) with a Terratec 3.85m-diameter rock slurry machine. The TBM has been advancing steadily


on the PST-1 alignment and completed approximately 4.5km of tunnelling. It will undertake a final 1.2km-long drive to finish the remaining section of the tunnel. The project, overseen by the


Brihanmumbai Municipal Corporation, involves the construction of a 3.2m i.d. tunnel with the alignment running below busy road networks and existing residential and commercial developments.


CRCHI progress in Sicily ITALY - An EPB TBM developed by CRCHI has completed its first tunnelling drive on the Messina-Catania railway project in Sicily – and the first TBM breakthrough on the section. The 9.36m-diameter machine – one of


four deployed – has completed 2.44km of tunnelling on a 12.54km-long section. The long drive passed through complex geology including shale, conglomerate, basalt, and sandstone, with uniaxial compressive strength (UCS) ranging from 4MPa - 45MPa. CRCHI’s R&D team worked with the


construction contractor to develop the tunnelling machine, which it said includes ‘green’ tunnelling concepts and technology, such as: a permanent magnet synchronous drive; high-stability power supply; continuous tunnelling; automatic equipment management; intelligent excavation parameter control; automatic segment lifting; a super high-pressure rescue system; and, automatic gantry steering. During excavation, work was halted at


intervals to monitor the potential presence of arsenic compounds in the strata. Through identifying and mitigating risks and holding on-site technical briefings, progress was maintained. The TBM achieved a maximum daily


advance of 30.6m, and a maximum monthly advance of more than 500m.


TBMs prepare in Sydney AUSTRALIA - The TBMs that will excavate Sydney’s next harbour crossing are in the final stages of assembly. The two TBMs, which will dig the final


section of the Western Harbour Tunnel, are being built in the launch chambers beneath Birchgrove Oval that are 28m-high, 21m-wide and 120m-long, TBMs ‘Patyegarang’ and ‘Barangaroo’ are


to bore twin, 1.5km-long motorway tunnels between Birchgrove and Waverton, up to 50m below sea level. Precast concrete segments are being manufactured at a facility in western Sydney. Assembly of Patyegarang is halfway, with


its 15.7m-diameter cutterhead weighing 462 tonnes. The TBM is expected to begin its drive under the harbour in mid-2026. Assembly of TBM Barangaroo is


following. The TBM is expected to be launched in H2-2026. Overall excavation across the Western


Harbour Tunnel project is more than three- quarters complete. The 6.5km-long tunnel is planned to open to traffic in 2028.


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