Singapore’s Land Transport Authority (LTA) has announced the beginning of work on phase one of the Cross Island Line (CRL), the island’s eighth and longest fully underground metro route.

When complete, the US$30bn line will be more than 50km long and will serve the eastern, western and north-eastern corridors by linking Jurong Lake District, Punggol Digital District and Changi.

The project is being built in three phases. The first, lasting around seven years, will cover 29km and will have 12 stations from Aviation Park to Bright Hill. It will interconnect with the East-West, North-East, North-South and the Thomson-East Coast lines.

The LTA is presently issuing tenders for phase two, which comprises six stations from Turf City to Jurong Lake District; engineering studies are in progress on the third phase.

To improve productivity and safety, LTA said it will use a trenchless construction method, which aims to minimise surface settlement during tunnel excavation.

LTA added that it will be exploring other innovative construction methods such as the use of virtual reality, augmented reality and computer simulation tools to “enhance capabilities and facilitate coordination”.

The full CRL is expected to be used by 600,000 passengers daily after the first phase begins operation, increasing to more than 1 million when the entire line is finished.