Tunnel updates - CR106, CR109, CR111, CR112 & CR116

CRL1 tunnel chart as of end-2025, to the team's best knowledge.

Tunneling works along the Cross Island Line (CRL)'s phase 1 have been progressing well, thanks to the favourable soil conditions in the eastern side of the island. Soil here is typically composed of old alluvium, great for tunneling as seen through the quick work made of tunnels under several contracts of late. 

August 2023 - A view of the displays within the CRL1 Project Information Centre. The display
on the left shows the Soil Profile along the CRL1.

A screenshot of the Soil Profile along CRL1.
Source: CRL1 Virtual PIC

Old Alluvium is a dense and strong material, capable of supporting the surroundings while tunneling work is being carried out. While strong, it is also easier to tunnel through than Bukit Timah Granite, an extremely hard rock that dominates the soil profile of Western Singapore. The transition from Old Alluvium to Bukit Timah Granite takes place in the vicinity of Ang Mo Kio and Teck Ghee.

With the favourable Old Alluvium in Eastern Singapore, here are some updates on tunneling work across CRL1.

• Contract CR106 - The second tunnel boring machine (TBM) has passed under housing blocks and is in the vicinity of Loyang Avenue.
• Contract CR109 - The westbound TBM has completed its second & final drive. Eastbound TBM was boring underneath Tampines Road in the vicinity of Tampines Dormitory.
• Contract CR111 - Both TBMs have completed their drives towards Hougang station.
• Contract CR112 - According to the Land Transport Authority (LTA), both TBMs have completed their drives toward Serangoon North station.
• Contract CR116 - As of end-November, the TBM's second drive was 63% completed.

CRL - A snapshot in October 2025

Overview of CRL1 stations CR4 - CR12 as at October 2025.
Top (L - R): CR4 – Pasir Ris East, CR5/CP1 – Pasir Ris, CR6 – Tampines North
Middle (L - R): CR7 – Defu, CR8 – Hougang, CR9 – Serangoon North
Bottom (L - R): CR10 – Tavistock, CR11 – Ang Mo Kio, CR12 – Teck Ghee

Overview of CPE stations CP2 - CP4 & CRL2 stations CR16 - CR19 as at October 2025.
Top (L - R): CP2 – Elias, CP3 – Riviera, CP4 – Punggol
Middle (L - R): CR16 – Maju, CR207 – Twin bored tunnels, CR17 – Clementi
Bottom (L - R): CR18 – West Coast, CR210 – Twin bored tunnels, CR19 – Jurong Lake District

It's been a while since we've done such an extensive coverage of the Cross Island Line (CRL) across its three current phases that have been announced thus far, hence we thought we'd let October be our month of diversity. Updates for this month stretch from Pasir Ris East all the way to Punggol & Jurong Lake District. If you've been curious on how things were progressing, this post is for you. Do be ready, this update's kind of MEGA.

CRL - A snapshot in August 2025

Overview of CRL1 stations CR3 - CR10 as at August 2025.
Top (L - R): CR3 - Loyang, CR4 - Pasir Ris East
Middle (L - R): CR5/CP1 - Pasir Ris, CR8 - Hougang
Bottom (L - R): CR9 - Serangoon North, CR10 – Tavistock

Overview of CRL1 station CR11 & CRL2 stations CR17 - CR19 as at August 2025.
Top (L - R): CR11 – Ang Mo Kio, CR207 - Launch shaft
Middle (L - R): CR17 - Clementi, CR18 - West Coast
Bottom (L - R): CR210 - Launch shaft, CR19 - Jurong Lake District

Roughly about three-quarters into the year, how has progress been along the Cross Island Line? We take a closer look at some of the key sites along the line in both phases 1 and 2 in this August look-back.

CRL - A snapshot in July 2025

Overview of CRL1 works under contracts CR106 - CR117 as at July 2025.
Top (L - R): CR106 - Loyang, CR4 - Pasir Ris East, CR5/CP1 - Pasir Ris, CR6 - Tampines North
Middle (L - R): CR110 – Large diameter tunnel, CR7 - Defu, CR8 - Hougang, CR9 - Serangoon North
Bottom (L - R): CR10 – Tavistock, CR11 – Ang Mo Kio, CR12 - Teck Ghee, CR13 - Bright Hill

There's a fair bit to update in this snapshot of the Cross Island Line (CRL) for July 2025. This update will mainly focus on progress along phase 1 of the line, the section with the most progress thus far due to the section's earlier announcement, contract award and commencement in general. Nonetheless, tunneling is also underway across all announced phases thus far, so we will touch a little on the progress made on that front thus far. All this & more after the jump.

CRL - A snapshot in May 2025

An overview of CRL1 contracts CR101 - CR111 as of May 2025.
Top (L - R) : CR101 - Changi East Depot, CR102 - Tunnels, CR103 - Aviation Park station
Middle (L - R) : CR106 - Loyang station, CR107 - Pasir Ris East station, CR108 - Pasir Ris station
Bottom (L - R) : CR109 - Tampines North station, CR110 - Large bored tunnel, CR111 - Defu station

An overview of CRL1 contracts CR112 - CR117, CPE contracts P102 & P103 and CRL2 contract CR202 as of May 2025.
Top (L - R) : CR112 - Hougang station, CR113 - Serangoon North station, CR115 - Tavistock station
Middle (L - R) : CR116 - Ang Mo Kio station, N109A - Teck Ghee station, CR117 - Bright Hill station
Bottom (L - R) : P102 - Elias station, P103 - Cripple siding, CR202 - Large bored tunnel

An overview of CRL2 contracts CR205 - CR211 as of May 2025.
Top (L - R) : CR205 - King Albert Park station, CR206 - Maju station
Middle (L - R) : CR207 - Tunnels, CR208 - Clementi station, CR209 - West Coast station
Bottom (L - R) : CR210 - Tunnels, CR211 - Jurong Lake District station

It has been a while since we've done a snapshot feature of the Cross Island Line (CRL), with our last being done in February for the Punggol Extension. Part of this stems for the works being "less noticeable", since the majority of this takes place underground and relatively out of sight. Another part is that it also appears that updates on the CRL aren't as popular compared to updates on other lines (granted, the above ground line updates are A LOT more interesting as you actually see things change with most monthly updates). Nonetheless, we thought it's time to see where the CRL is in progress with this rather comprehensive mid-year update.

CR116 - TBM assembly begins

 

March 2025 - Assembly of the slurry TBM that will bore tunnels for
the contract has commenced within the launch shaft.
Source: LinkedIn

Recently, we came across images of the slurry Tunnel Boring Machine (TBM) for contract CR116 being assembled within the contract's launch shaft. Located near the junction of Ang Mo Kio Avenues 3 and 6, the launch shaft was completed some time back following excavation 25 metres down to the base level. Before TBM assembly could commence, adits were constructed to allow for the machine to be jacked forward to commence tunnel construction. This method is similar to the technique previously employed for several launch sites along the Downtown Line's Stage 3 section, with the use of circular shaped launch shafts near the former Tampines Prison (Prison shaft), Tampines Stadium (Stadium shaft) and Pan Island Expressway exit near Upper Changi Road (PIE shaft).

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.

CRL - A snapshot in August 2024

 

An overview of 2 CRL1 contracts as of August 2024.
Top: Changi East depot
Bottom: Contract CR110 launch shaft at Paya Lebar Air Base

Overview of CRL1 stations CR3 - CR11 as of August 2024.
Top (L - R): CR3 - Loygang, CR4 - Pasir Ris East, CR5/CP1 - Pasir Ris
Middle (L - R): CR6 - Tampines North, CR7 - Defu, CR8 - Hougang
Bottom (L - R): CR9 - Serangoon North, CR10 – Tavistock, CR11 – Ang Mo Kio

Overview of CRL1 stations CR12 – CR13, CPE stations CP2 – CP4 & CRL2 stations CR15 –
CR18 as of August 2024.
Top (L - R): CR12 – Teck Ghee, CR13 – Bright Hill, CP2 – Elias
Middle (L - R): CP3 – Riviera, CP4 – Punggol, CR15 – King Albert Park
Bottom (L - R): CR16 – Maju, CR17 – Clementi, CR18 – West Coast

With the award of contract CR207 for tunnels between Maju and Clementi stations in August, all civil contracts across the Cross Island Line (CRL)'s phases 1, 2 and Punggol extension have been awarded. Work on phase 1 and the Punggol extension were well underway while works along phase 2 were at different stages owing to the contract award progress.

CR116 - Ang Mo Kio update Q2 2024

20 June 2024 - A view of heavy machinery on the south side of the station in end-Q2.

The site of contract CR116 has been a busy one over the past quarter, with preparation works underway to begin construction at Exit 7 outside AMK Hub. This site has been one of the few that has yet to begin construction in any form while works progressed at the rest of the station site. One of the major observations over the course of the quarter was the slow ramping down of diaphragm walling works on the southern edge of the station as the works approached completion. Join us as we look back on the progress made over the past quarter.

CRL - A snapshot in July 2024

Overview of CRL1 contracts CR102 - CR115 as of July 2024.
Top (L - R):  CR102 - Tunnels at Changi East, CR4 - Pasir Ris East, CR5/CP1 - Pasir Ris
Middle (L - R): CR6 - Tampines North, CR110 – Large diameter tunnel, CR7 - Defu
Bottom (L - R): CR8 - Hougang, CR9 - Serangoon North, CR10 – Tavistock 

Overview of CRL1 contracts CR116 & N109A, CPE contracts P102 - P103 & CRL2 contracts
CR205 - CR211 as at July 2024.
Top (L - R): CR11 - Ang Mo Kio, CR12 - Teck Ghee, CP2 - Elias
Middle (L - R): P103 Cripple siding, CR15 - King Albert Park, CR16 - Maju
Bottom (L - R): CR17 - Clementi, CR18 - West Coast, CR19 - Jurong Lake District

July was a momentous month for the Cross Island Line (CRL). All civil contracts for the construction of stations across phases 1, 2 and the Punggol extension were awarded. Along phase 1, several contracts were in the midst of Tunnel Boring Machine (TBM) assembly and subsequent launch as well. In this update, we take a brief look at the progress made across the line's first few phases.

Tunnel Boring Machines of CRL1

Tunnel Boring Machines of Cross Island Line Phase 1.
Top (L - R) : Contract CR102, Contract CR106
Middle (L - R) : Contract CR105, Contract CR115, Contract CR110
Bottom (L - R) : Contract CR109, Contract CR116

Tunnel Boring Machines, also known as TBMs, have been described as mechanical moles or earthworms that dig through the ground, leaving behind hollow concrete tubes through which trains eventually run. These huge machines often work their way along the future MRT lines, most members of the public unaware of their existence right beneath them. 

TBMs used on previous MRT projects were huge at approximately 6.3m in diameter. The ones used on the Cross Island Line (CRL) are even bigger, owing to the extra space required to run an additional rail supplying the trains with power along the top of the eventual tunnel. These will measure at around 7.22m for single tube tunnels that carry one track and 12.66m for large diameter tube tunnels that carry several tracks within.

CRL - A snapshot in May 2024

Overview of CRL1 stations CR4 - CR7 as at May 2024.
Top (L - R): CR4 - Pasir Ris East, CR5/CP1 - Pasir Ris
Bottom (L - R): CR6 - Tampines North, CR7 - Defu

Overview of CRL1 stations CR8 - CR11 as at May 2024.
Top (L - R): CR8 - Hougang, CR9 - Serangoon North
Bottom (L - R): CR10 – Tavistock, CR11 – Ang Mo Kio

Overview of CRL1 stations CR12, CR13, CR15 & CR17 as at May 2024.
Top (L - R): CR12 - Teck Ghee, CR13 - Bright Hill
Bottom (L - R): CR15 - King Albert Park, CR17 - Clementi

Another week, and another month goes by. We're now clearly heading towards the middle of the year with June underway. Here's a look back at the progress made at the various Cross Island Line station sites in May 2024. There's a bit more to see now that some of the Tunnel Boring Machines are in the ground and beginning their boring journeys through the east to construction the line.

CR116 - Ang Mo Kio update Q1 2024

 

21 March 2024 - An aerial view of Ang Mo Kio station's paid transfer link, Exit 2 & 6's worksite
next to the existing North-South Line station.

Q1 of 2024 has seen work at Ang Mo Kio station ramping up ahead of more modifications to the existing North-South Line (NSL) station. Diaphragm wall construction work has commenced near the existing NSL station as well, ahead of the planned switch over to diaphragm wall construction along the northern side of Ang Mo Kio Avenue 3 in the later half of the year.

CRL - A snapshot in April 2024

 

Overview of CRL1 stations CR4 - CR13 as of April 2024.
Top (L - R): CR4 - Pasir Ris East, CR5 - Pasir Ris, CR6 - Tampines North
Middle (L - R): CR7 - Defu, CR8 - Hougang, CR9 - Serangoon North
Bottom (L-R): CR10 - Tavistock, CR11 - Ang Mo Kio, CR13 - Bright Hill

We're pretty much done with April of 2024 - what a quick first third of the year it has been! Things are quickly becoming serious over along the Cross Island Line (CRL)'s first phase of 12 stations stretching from Aviation Park to Bright Hill with tunnel boring machines (TBMs) being delivered to site and lowered into launch shafts, station box excavation starting and bored piling continuing. We'll do a brief overview of the CRL1 stations as of the end of April 2024. More after the jump!

CRL - A snapshot in March 2024

Overview of CRL1 stations CR4 - CR13 as at March 2024.
Top (L - R): CR4 - Pasir Ris East, CR5/CP1 - Pasir Ris, CR7 - Defu
Middle (L - R): CR8 - Hougang, CR9 - Serangoon North, CR10 - Tavistock
Bottom (L - R): CR11 – Ang Mo Kio, CR12 - Teck Ghee, CR13 - Bright Hill

Overview of CPE & CRL2 stations CP2 - CP4 & CR14 - CR19 as at March 2024.
Top (L - R): CP2 - Elias, CP3 - Riviera, CP4 - Punggol
Middle (L - R): CR14 - Turf City, CR15 - King Albert Park, CR16 - Maju
Bottom (L - R): CR17 - Clementi, CR18 - West Coast, CR19 - Jurong Lake District

It's been a whirlwind first quarter of the year. We take the opportunity to check in on the progress of the various construction sites along the Cross Island Line (CRL)'s various phases in the month of March and provide a glimpse at the progress being made. Do check out the various projects after the jump.

CRL - A snapshot in February 2024

 

Overview of CRL1 stations CR3 - CR13 as at mid-to-late February 2024.
Top (L - R): CR3 - Loyang, CR5/CP1 - Pasir Ris, CR6 - Tampines North
Middle (L - R): CR7 - Defu, CR8 - Hougang, CR9 - Serangoon North
Bottom (L - R): CR10 – Tavistock, CR11 – Ang Mo Kio, CR13 - Bright Hill

Overview of CPE & CRL2 stations CP02 - CP04 & CR15 - CR18 as of mid-to-late February 2024.
Top (L - R): CP02 - Elias & CP03 - Riviera
Middle (L - R): CP05 - Punggol, CR15 - King Albert Park, CR16 - Maju
Bottom (L - R): CR17 - Clementi & CR18 - West Coast

The first few months of the year have quickly past and we're slowly getting back into the monthly routines. Here's a snapshot update of the Cross Island Line (CRL)'s various stages of construction for the month of February with work started on phase 1 and the Punggol Extension. The latest phase announced - phase 2 - has also begun early works which we also explore in this update.

CRL1 year-end update 2023

 

10 stations of the Cross Island Line's phase 1 as at end-2023.
Aviation Park & Defu are not represented in this post.

Sorry this post was a little delayed - got caught up between travelling & work. But we're here and made it to 27th December after all. For this post, we're covering the 10 stations that we have the most pictures of along the Cross Island Line (CRL)'s phase 1. The 2 stations not covered in the post today are Aviation Park and Defu. We may cover them at a later time. Nonetheless, it has been an eventful year for the CRL with the groundbreaking ceremony being held in January 2023. Construction has been well under way at all sites with work in full swing for the construction of the earth retaining & stabilising structures (ERSS). Several intermediate launch shafts have been built as well and excavation commenced at a few sites in particular.

Please be fair warned that this post is a mega-post and extremely photo-heavy. It may suck up a lot of your bandwith after the jump.

CRL1, CPE & CRL2 - A snapshot in October 2023

 

Top (L - R): CR105 - Large diameter tunnel, CR3 - Loyang, CR4 - Pasir Ris East
Middle (L - R): CR5/CP1 - Pasir Ris, CR6 - Tampines North, CR7 - Defu
Bottom (L - R): CR8 - Hougang, CR9 - Serangoon North, CR10 – Tavistock

Top (L - R): CR11 - Ang Mo Kio, CR12 - Teck Ghee, CR13 - Bright Hill
Middle (L - R): CP2 - Elias, CP3 - Riviera, CR15 - King Albert Park
Bottom (L - R): CR16 - Maju, CR17 - Clementi, CR18 - West Coast

Here's a look at the progress made at the various Cross Island Line (CRL) sites across Phases 1, 2 & the Punggol Extension in October 2023.

CR116 - Ang Mo Kio update Q3 2023

 

19 August 2023 - A view of the progress of construction around the existing North-South Line
(NSL) Ang Mo Kio station.

Over Q3, works have progressed at the Ang Mo Kio station site. Significant progress has been made at the launch shaft site as well as several exit worksites where diaphragm wall excavation works have commenced. Soil treatment work is also being carried out at Exit 8 ahead of excavation there.

CRL1 - A snapshot in September 2023

 

Overview of CRL1 stations CR4 - CR11 & Contract CR110 as at September 2023.
Top (L - R): CR4 - Pasir Ris East, CR5/CP1 - Pasir Ris, CR6 - Tampines North
Middle (L - R): CR7 - Defu, CR8 - Hougang, CR9 - Serangoon North
Bottom (L - R): CR10 – Tavistock, CR11 – Ang Mo Kio, CR110 – Large diameter tunnel

Our snapshot update for the Cross Island Line (CRL) phase 1 in the month of September 2023 is here. We have also begun the Q3 updates for some stations, so those updates will be more detailed than the ones reflected here. Nonetheless, do enjoy the brief update on the 9 contracts for September.