The incredible new £23.8bn train line that's causing chaos to build

A new 35-mile stretch of underground metro train beneath Singapore is proving to be a major headache for developers.

The tiny southeast Asian island already has a revered metro system - the Mass Rapid Transit - but it is being expanded with the new 21-station Cross Island Line, which will be the longest once complete. It should reduce journey times across the island by up to half.

It is to be opened over two phases, firstly trains from Aviation Park to Bright Hill opening from 2030 and later from Punggol to Jurong Lake District by 2032. 

It will serve new areas and take pressure off the existing East-West Line.

Construction work started in January 2023, however, its development has become very difficult due to a lack of space in Singapore, which is smaller than London. 

Singapore is the third most densely populated country in the world after Macao and Monaco.

The Central Catchment Nature Reserve is one of only a few green lungs in the island city and is highly prized due to having about 1,600 plant species and many animals such as the Asian Fairy-bluebird and the banded leaf monkey.

But, it is proving a sticking point for the new Metro line, which was first announced by the Land Transport Authority (LTA) more than a decade ago in 2013.

The tunnel is having to go beneath the natural park, to the horror of wildlife campaigners. This means tunnelling through deep bedrock, which makes for stronger tunnels, but is extremely difficult. It also means locating the depth of the bedrock first, by drilling down until it is hit.

This has meant turning part of the reserve into a construction site by clearing a path to allow access by borehole machines with entry and exit points.

The LTA has spent six years working with the Nature Society of Singapore to work out how to build the tunnel without damaging the reserve.

They have been able to use an existing trail for borehole machinery to do bedrock tests.

The line is now being built as far down as 70 metres, more than twice the average depth of an MRT line.

The new stop at Pasir Ris will be the deepest station of the entire network at 47 metres.

One side of the station wall will be directly between two active viaducts for the East-West line, creating issues of water seepage.

As a result, concrete slabs have had to be poured in sequences so that when the middle slabs are created, a trench-cutting machine makes a notch in the neighbouring slabs. 

This is so that when the middle slab is poured, concrete fills the notch, creating a seal against water.

A LTA spokesperson said: "CRL2 will provide greater accessibility for those living in the west, including areas such as Sunset Way and West Coast that are not currently served by an MRT line.

"Two of the six stations will be interchange stations, with King Albert Park station connecting commuters to the Downtown Line, and Clementi station to the East-West Line.

"With the improved connectivity, CRL2 will shorten travel times for commuters travelling to and from the western parts of Singapore. Together with the CRL1 and CRL – Punggol Extension, CRL will offer alternative travel options for commuters and help to redistribute commuter load across Singapore’s entire rail network."