CRL1 - TBM Season

Contract CR102 TBMs during the assembly phase at the launch shaft.
Source: STEC

A happy new year to all our readers & followers! Recently, we have come across a few new images of tunnel boring machines (TBMs) for the Cross Island Line (CRL) phase 1. Coupled with recent deliveries to sites at Hougang, Ang Mo Kio and Defu, its definitely TBM season for the CRL. What better way to begin the new year than by taking a look at all the machines responsible for building the tunnels for the upcoming CRL1? More of them after the jump.

Specific to CRL1, TBM procurement was handled differently with the Land Transport Authority (LTA) opening a tender for the supply of TBMs for the various contracts within. Under contract CR120, various civil contracts for the construction of stations & tunnels were packaged together for a bulk purchase of machines. Ultimately, the tender was won by two companies - Shanghai Tunnel Engineering Co (STEC) and China Railway Equipment Group (CREG).

Breakdown of the quantities of machines to be supplied & types of machines. EPB machines
are Earth Pressure Balance machines.

Contracts CR105, CR110, CR116 and CR117 were not included in the procurement exercise while contract CR101 and CR113 do not include tunneling works. The contractor for contract CR116 at Ang Mo Kio eventually procured a slurry TBM machine from CREG as well.

Contract CR102 - CRL Tunnels between Changi Airport East, Aviation Park & Changi East Depot
Under this contract, 5 tunnels will be constructed using 4 EPB machines - with 1 machine performing double duty. Tunneling works would commence from 2 launch shafts located at the Changi East Industrial Zone and along Aviation Park Road. Machines for this contract were supplied by STEC and had cutterheads in varying colours - 2 bearing red, 1 in green and 1 in blue.

July 2024 - Participants at the International Joint Research Laboratory of Earthquake Engineering
(ILEE) summer programme pictured in front of a TBM for contract CR102 at the factory in China.
Source: LinkedIn

June 2024 - Lifting of the TBM cutterhead for one of the contract CR102 TBMs at the launch
shaft.
Source: LinkedIn

21 July 2024 - One of the TBMs within the Changi East Industrial Zone launch shaft.
Source: LinkedIn

Contract CR108 - Pasir Ris
This contract will utilise a single EPB TBM to construct tunnels connecting Pasir Ris and Pasir Ris East stations. Due to the lengthy section of cut & cover tunnel required for the transition tunnels, where the Punggol Extension tracks climb upwards and have turnouts connecting the spur line with the main line, the bored tunnel section between the stations is relatively short. As such, the single STEC machine will be used to bore the tube tunnels connecting the stations twice.

Undated image - The contract CR109 EPB machine during the factory acceptance test.
Source: STEC

Undated image - Another view of the EPB machine for contract CR108.
Source: STEC

Photos of TBM Cutterheads for contracts CR102 (left) & CR108 (right).
Source: STEC

Photos of TBM cutterheads for CR102 (left) and CR112 (right).
Source: STEC

Contract CR111 - Defu
Another contract to recently have its TBM delivered is contract CR111 for the construction of Defu station and tunnels connecting to Hougang station. The factory acceptance test was conducted in October 2024 and the TBM was seen on site in December 2024. A large crane was also spotted along Tampines Road, where the contract's launch shaft is located, to sequentially lower TBM segments below ground. We understand that approximately 2 TBMs, built by CREG, are to be used but currently have only managed to sight one thus far.

23 October 2024 - The TBM to be used for contract CR111 at the factory during the equipment
acceptance test.
Source: CCM News

14 December 2024 - Sections of the TBM on site.

14 December 2024 - Part of the TBM shield covered in blue tarpaulin.

14 December 2024

30 December 2024 - The location of various TBM segments within the site had moved and the
large crane can be seen on site.

30 December 2024

30 December 2024 - The TBM cutterhead on site.

Contract CR112 - Hougang

We recently published a few articles on the contract CR112 TBMs at Hougang station. Since then, we have come across a few more pictures of the TBMs built by STEC. Since then, works to lower the second machine into the launch shaft had taken place, with both TBMs lowered by the end of 2024. It appears that the first TBM was lowered to be assembled for the Changi-bound tunnel while the second TBM lowered would be assembled for construction of the Tuas-bound tunnel. Both TBMs will construct tunnels linking the Hougang station to Serangoon North.

The 2 TBMs for contract CR112 while still in the factory during the acceptance test phase.
Source: CR112 Telegram group

13 December 2024 - Tail shield of the first TBM to be lowered seen on site.

13 December 2024 - A close up view of the tail shield prior to being lowered into the launch
shaft.

13 December 2024 - Segments of the second TBM to be lowered still at the surface.

10 December 2024 - Part of the TBM back up gantry being lowered into the launch shaft.
Source: STEC

21 December 2024 - An aerial view of the Hougang station site with parts of the TBM shield visible.

21 December 2024 - Tail shield of the second TBM to be lowered visible on site.

21 December 2024 - Segments of the second TBM are no longer seen at the staging area.

22 December 2024 - An alternate view of the construction site & staging area.

22 December 2024 - Tail shield of the second machine to be lowered in view.

Contract CR116 - Ang Mo Kio
A recent delivery last month was to the site of contract CR116's intermediate launch shaft at the junction of Ang Mo Kio Avenues 3 and 6. The slurry TBM was delivered in parts and was manufactured by CREG, although not part of the contract CR120 order. The single TBM will be used for 4 drives from the launch shaft towards Teck Ghee station first and then towards Ang Mo Kio station subsequently.

17 December 2024 - Notice to stakeholders of the TBM delivery to site.
Source: CR116 Telegram group

25 December 2024 - Segments of the TBM visible on site.

25 December 2024 - Segments of the TBM covered in dark blue tarpaulin.

Contract N109A - Teck Ghee
Finally, although contract N109A for the construction of Teck Ghee station would not see rail tunnels being constructed, a TBM is being used to construct two pedestrian subways linking station exits in Bishan-Ang Mo Kio Park with the rest of the station structure. However, the TBM used here bears a rectangular shape and is known as a Rectangular TBM (RTBM), a relatively new innovation that has been gaining wider acceptance and use lately. RTBMs were first used in construction along the Thomson-East Coast Line (TEL), most notably at Havelock and Stevens stations, but also at Marina Bay interchange station.

The RTBM at Teck Ghee station site is currently being used to bore the pedestrian subway linking Exit 3 with the main station box. It will subsequently be used for a similar operation on the opposite side of Ang Mo Kio Avenue 6 and Marymount Road, to connect Exit 2 with the station box. Both pedestrian subways will cross underneath Ang Mo Kio Avenue 1. RTBMs operate differently from conventional TBMs in a method more similar to pipe jacking. This method sees fully completed segment rings being placed behind the RTBM's shield and the machine and tunnel rings are then shoved forwards by a thruster ring from within the launch shaft. Work has since begun on the first subway link.

19 October 2024 - A view of the RTBM before launching works saw the machine begin its
drive underneath Ang Mo Kio Avenue 1.
Source: Concrete Innovators Co Pte Ltd

19 October 2024 - An RTBM has many more cutterheads than a regular TBM.
Source: Concrete Innovators Co Pte Ltd

19 October 2024 - Sections of the rear of the TBM being assembled.
Source: Concrete Innovators Co Pte Ltd

19 October 2024 - A tunnel ring segment being lifted for transport to site.
Source: Concrete Innovators Co Pte Ltd

31 December 2024 - A view from within the pedestrian subway link being bored to connect
Exit 3 with the main station box at Teck Ghee.
Source: LinkedIn

We have mostly covered the other contracts with TBMs - contracts CR105, CR106, CR109 & CR110 - in another post with images that we have come across thus far. Works for contracts CR105 & CR109 had previously commenced, with tunneling works underway. The TBM for contract CR110, which will see tunnels constructed from the Paya Lebar Air Base eastern shaft to Defu station, had recently completed segment lowering operations at the launch shaft.

One remaining contract - CR117 for the construction of Bright Hill station and connecting tunnels to Teck Ghee station - has yet to have its single slurry TBM delivered. Nonetheless, works were progressing well for the TBM launch shaft and noise enclosure located just across from Eunoia Junior College. When we sight the TBM, we'll be sure to perform another round of updates to keep you informed.

This post will also be available on Instagram & Facebook on 3 January 2025.