Costing $18 billion and spanning 30km long, the Thomson Line, with 22 stations, will run underground from Woodlands to Gardens by the Bay and open in three phases from 2019 to 2021.

The Thomson Line will serve estates in the northern and central parts of the island, and is expected to ease crowding on the North-South Line and provide commuters with alternatives during service disruptions, said Transport Minister Lui Tuck Yew. For example, he explained how residents from Springleaf estate in Sembawang will need only 35 minutes to travel to Great World City, compared to the current 60 minutes.

The line holds six interchange stations, thus providing commuters more alternative routes and minimise inconvenience during disruptions. To date, 22 of 25 major civil contracts have been awarded at a cost of $6.5 billion, and the remaining three will be awarded by this year. In addition, the Land Transport Authority (LTA) has ordered 91 four-carriage trains, amounting a total of $749 million.

Eventually the Thomson Line would be linked to Johor Baru via a rapid transit system at Woodlands North station. When The Straits Times enquired for an update, Mr. Lui revealed details of Woodlands North station have been finalised, and progress is dependent on the Malaysian side.

For the first time in Singapore, Japanese contractor Taisei Corporation will use ice walls, in constructing Marina Bay station to prevent water seepage during tunnelling works. The process involves pumping refrigerant into pipes that will be slotted in the ground to freeze groundwater, reported The Straits Times.

For a 40-metre stretch, the Thomson Line will run below tunnels for the Circle and North-South Line, as such freezing the ground during excavation will ensure groundwater does not seep in and prevent the ground from becoming unstable.

Other engineering challenges include carrying out mining works under the existing Orchard station, requiring engineers to ensure that surrounding structures are not affected and rail operations are not disrupted.

At the ground breaking ceremony yesterday, the Transport Minister also announced a new North-South Line station named 'Canberra', will be constructed between Yishun and Sembawang. More details on its exact location and commencement date will be revealed at a later juncture.