New Tunnel Boring Machines (TBMs) to be used on the Ümraniye – Ataşehir – Göztepe Metro Line are Ready The on-site assembly of the two 6.56m diameter Terratec EPBMs (Earth Pressure Balance Shield Machines) to be used to construct the Ümraniye-Ataşehir-Göztepe line, which has recently been added to Istanbul metro line as part of the expansion project undertaken by the Gülermak, Nurol and Makyol Joint Venture, is about to be completed. In addition to these EPBMs, two other machines that were previously acquired for the project will enter into service in mid-May.