The upgrades, which cover 182km of line, include the installation of ETCS, electronic interlockings and automatic train supervision (ATO) and a new traffic control centre (CTC) for the line, which connects Eskişehir, about 260km east of Ankara, to Balikesir near the Aegean coast.
The work, which was carried out by Alstom, covers the first five sections of the upgrade project, under a €88.9m contract awarded in November 2011. The remaining 146km is expected to be commissioned by the end of 2021.
The project was originally expected to take around 36 months, with a planned completion date of November 2014, but was subsequently delayed due to site work conditions and additional scope added to the contract.
Alstom also supplied level crossing systems, technical equipment buildings and power distribution and supply systems under the same contract.
The upgrades will enable the operation of trains at speeds of up to 160km/h, as well as offering increased capacity.