Tunnelling for the mass rapid transit (MRT) system in Jakarta will begin in August.
The project will involve four tunnel boring machines (TBMs), which will excavate tunnels 12 to 24m underground.
Tunnelling of the 6km underground section is expected to be complete by the end of 2016, with the TBMs travelling at a rate of 8m a day.
The commuter rail network will stretch approximately 110.8km and will include construction of north-south and east-west corridors.
The north-south corridor will run from Lebak Bulus to Kampung Bandan and will be approximately 23.8km long. The route will be completed in two phases.
The first phase, which will involve the construction of 13 stations along 15.7km, is scheduled to be operational by 2018. The second phase to construct 8.1km of railway is expected to be completed by 2020.
A feasibility study is in progress for the east-west corridor, which is scheduled to be operational by 2024-2027.