A fleet of TERRATEC EPBMs gear up for action on Istanbul’s new Halkali airport metro connection


TERRATEC is pleased to announce the delivery of a further two new 6.56m diameter Earth Pressure BalanceTunnel Boring Machines (EPBMs) for the ongoing expansion of Istanbul’s Metro system, in Turkey, following successful factory acceptance testing earlier this week. The new EPBMs, along with two other sister machines that have already been delivered to the project, will bring the number of TERRATEC machines working concurrently on the city’s metro to a total of nine.

The new TBMs will be used by the Halkali-Yeni Havalimani Metro JV (consisting of Cengiz İnşaat, Kalyon and Kolin) on the Halkali-Istanbul New Airport metro line, which was awarded to a consortium comprising Özgün Yapı and Kolin by the Turkish Ministry of Transport and Infrastructure (AYGM). The 31km-long line, along with 6 new stations and connections, will form the western-leg of the new M11 Line that runs from the recently opened third International Airport on the European side of the city southwards to Halkali (which will also be the final terminus of the new Marmaray railway).

The robust TERRATEC TBMs have versatile mixed-face dome-style cutterheads that have proven to work extremely effectively in Istanbul’s mixed geology – which includes sandstones, siltstones, limestones and volcanic rock – as well as other state-of-the-art features such as VFD electric cutterhead drives, tungsten carbide soft ground cutting tools that are interchangeable with 17’’ roller disc cutters, high torque screw conveyors and active articulation systems.

As the TBMs progress, they will install 1,500mm wide by 300mm thick pre-cast concrete lining rings, which consist of five segments plus a key.

“Terratec is excited to be providing yet more machines to metro projects in Istanbul,” says TERRATEC Sales & Marketing Director, Bruce Matheson. “We are confident they will perform as well as previous machines have in the city and we look forward to breaking more records for on-time delivery, quick assembly and excellent production rates.”


The Halkali-New Airport metro line is one of a number new metro lines currently being built in the city that will increase Istanbul’s current 145km Metro network to more than 480km. Members of the JV were so impressed with the performance of previous TERRATEC machines used on the Mecidiyeköy-Mahmutbey Metro, the Dudullu-Bostancı Metro Line and the Ümraniye-Ataşehir-Göztepe Metro contract – that they were keen to employ a further four TERRATEC machines on this latest project.

In March 2018, one the Dudullu-Bostancı TERRATEC EPBMs completed an outstanding advance of 19 rings in a single shift (equating to 28.5m of excavation in just 12-hours), accomplishing a new production record for a TBM of this size and class in Istanbul.

More recently, on the other leg of the new M11 International Airport metro line (the 37km-long Gayrettepe-New Airport metro line that is being constructed by the Kolin-Şenbay consortium), the refurbished TERRATEC S42 machine is going strong, achieving a best day of 33 rings (46m) earlier this month.


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