Launch Shafts Backfill

The Mandai Depot is nearing completion with the final structural steel works completed. Fit-out and trackworks continue, with the commencement of landscaping, fencing and driveway works since the beginning of the year. The delivery of the first passenger train to the depot is scheduled in June.

Backfilling works for LS2 and the Sembawang Airbase C&C tunnel site, as well as casting of the escape shaft 1 structure have completed to ground level. Demobilization of the T206 sites are underway.

Mandai Depot

Mainline Trackworks

Trackworks at the depot have been ongoing for over a year now, with majority of the works mostly completed across the depot. CTCI has begun taking over access along the completed portions of tunnel between T206-T208, with trackworks commencing along the reception tunnels 1&2 towards Sembawang Airbase. The permanent tunnel structure within the launch shafts are being constructed over as a conclusion to the civil works.

Mandai Depot

Sembawang Airbase Backfill

Backfilling works are underway at SBAB upon completion of the tunnel roof structure. As the installation of the SWC brackets in the tunnels complete by the next quarter, the interlinking tunnel structure within each launch shaft will be cast to provide a complete substructure tunnel linkage across TEL1 for trackworks to proceed on to the reception tracks and mainline from Mandai Depot.

S1-S2 removal with concurrent backfilling works at Sembawang Airbase C&C

TEL1 Tunnelling Completes

Bored tunnelling works have completed this month under Stage 1 of the project between Woodlands North, Mandai Depot and the Sembawang Airbase cut and cover tunnel site. 12 tunnel drives were launched using 3 Earth Pressure Balance machine 4 Slurry TBMs which bore through the weathered Bukit Timah Granite to complete the 8km network of mainline and reception tunnels beneath Woodlands.

For most of the tunnels, the basic structural completion (BSC) have already been achieved with the first stage concreting (FSC) for the track bed, together with brackets installation for the various SWC. Trackworks are slated to commence through the tunnels by the end of 2017, with the remaining SWCs gaining access from the 2nd half of 2018.

Mandai Depot Stabling Yard

Mandai Depot - TBM 3 Second Breakthrough

Tunnelling works for the T206 project are wrapping up with 8 of the 10 bored tunnels completed. Cross passage excavation and the first stage concreting works are taking place within the tunnels. Structural, fittings and trackworks are progressing at the depot.

Stabling Yard nearing structural completion

Mandai Depot - Trackwork Begins

Commencement of the line's largest system-wide contract, led by CTCI for the design, supply, construction, testing and commissioning of trackwork and third rail system, took place this quarter with the staging ground prepared at the Mandai Depot. This is the second back-to-back trackwork project awarded to the Taiwanese contractor, with a smooth transition of resources expected from the recently completed Downtown Line 3.

Structure for the stabling yard, bus parking deck and perimeter wall mostly completed

S-893 Reassembly

Having completed the Changi Bound tunnel from LS2 to Woodlands, the re-assembly of S-893 (TBM 1) is taking place at LS1 for the RT3 tunnel drive to Woodlands Station. The TBM is expected to launch next month and breakthrough by mid-2017. TBM 3 has been retrieved from Mandai Depot and is held at the surface of LS2, awaiting to be reassembled for the Changi bound tunnel drive to Woodlands South Station.

Launch Shaft 1/ ES1

Mandai Depot - TBM 3 Breakthroughs

The first Earth Pressure Balance TBM for the line broke through the retrieval point north of Mandai Depot last Saturday, completing the reception tunnel 3 drive from the launch shaft 1 (LS1). This is the fifth bored tunnel to be lined for the line, and is also the shallowest breakthrough point in the MRT construction history due to the unique utilization of TBMs for the construction of the reception tunnels leading to an at-grade depot.

Retrieval of the machine is underway for the subsequent tunnel drives from LS2 to Woodlands South station. Herrenknecht slurry machine S-893, together with TBM 5 for the Changi Bound drive from LS2 to Woodlands station and SBAB to Woodlands South station have completed similarly.

Lowering and installation of cradle for the retrieval of TBM 3 at Mandai Depot

Mandai Depot & T206 (III)

All 5 TBMs for the project have been launched and are excavating the mainline and reception tunnels. The single-span replacement POB along Woodlands Avenue 2 was launched on February 5. The old bridge will be demolished and have its piles removed ahead of the relaunch of TBM S-893 for the RT3 drive at the end of the year.

Replacement POB in construction along Avenue 2

Mandai Depot & T206 (II)

Tunnelling works on the mainline tunnels between LS2 and WDL are progressing well. S-893 has successfully completed the 3-week long installation of the backup gantries during the transition from the initial to main drive, and has now advanced over 70 rings. S-894 has advanced 11 rings from the launch shaft. A gantry crane has been installed over the ES1/LS1 prior to the lowering of the EPB TBM last month. The backup gantries site beneath the portal crane over the shaft, while the machine is being assembled beneath.

The entire SBAB C&C structure has reached the formation level and casting works are underway to cast the base slab. The second of STEC'S EPB pre-assembled machine has been delivered to the launch shaft and will likely commence the first drive along the reception tunnels judging from the soil investigation and preparatory works along the reception tunnel route.

The T206 team recently celebrated their 2 million accident free man-hours.

Portal crane and backup gantries in preparations of tunnelling works at LS1

Mandai Depot & T206

Excavation works progresses along the cut and cover structures along the T206 project.

Launch Shaft 1 & 2

The Changi Bound TBM has completed assembly works within the adit tunnel of LS2 and will launch by the middle of this month. Excavation of LS1 has completed and the team is now blasting the horizontal section on both ends for the adit tunnel. The depot-bound STEC EPBM is slated to commence tunnelling along RT3 by the end of the year.

SBAB C&C & Escape Shaft 2

The ES2 structure now has the entire S1 layer shored along its entire length. The north launch shafts at the Sembawang Airbase C&C tunnel has now been excavated down about 20 meters, close to the formation level with an approximate reduced level of 95.000. The gantry cranes have been installed around the launch shafts, and tunnelling here should commence by year end with the TBMs arriving and assembling in the 4th quarter.

Mandai Depot

Columns along the north end of the stabling area are currently being cast. The structure will feature 45 parallel tracks, more than thrice the width that of the Downtown Line's Gali Batu Depot. Each track will accommodate for 2 x 4 passenger cars to effectively house the entire fleet of the 43km Thomson-East Coast line. The depot has been intentionally over-designed for future fleet expansions should the need arises.

Mandai Depot, T201

T206 Piles and Excavates (II)

We are pleased to share that the T206 project has achieved a half-million accident free man-hours at the beginning of this year. We review the intensive work that have been accomplished thus far.

One of the significant milestone achieved includes the deep excavation of Launch Shaft 2, and completion of the circular earth retaining structure for Launch Shaft 1. The LS2 which is 30m deep, have been dug to a depth of about 20m so far and seem to have encountered rock. LS1, which will launch out the reception tunnels, has a shallower formation level.

A treatment plant is under construction between the 2 shafts. Excavation of the shafts would have completed by our next update. We can expect the gantry cranes to be assembled and TBMs delivered to the site by then. Towards the south, piling works continue at the Sembawang Airbase C&C.

Progress of SBAB and Mandai Depot

Launch Shaft 1 (left) and Launch Shaft 2 (right)

T206 Piles and Excavates

We gear up closer to the commencement of tunnelling works for the Thomson Line in this update. Excavation works for the Launch Shaft 2 (LS2) has just started after 6 months of drilling and piling. STEC has altered the design of the launch shaft from an initial rectangular box proposed by the A/E consultant into a double circular cell - similar to the proposed Dalvey LS at Stevens. The design omits the use of any temporary struts while a permanent concrete beam supports the compression forces of the shaft at its center. This is a significant milestone for the project and we expect excavation works to continue on throughout the next quarter. Works have yet to start on Launch Shaft 1.

T206 Tunnel Chart

Proceeding south, piling works are also in full swing at the Sembawang Airbase (SBAB), escape shaft and Mandai Depot. Kori has been subcontracted by STEC for shoring works under T206. In addition, Kimlun of Malaysia will be supplying the precast tunnel segments for the 10 tunnels within this contract.

Excavation of Launch Shaft 2

Piling works at the Sembawang Airbase C&C site and Avenue 12 Escape Shafts

Piling at Mandai Depot

Mandai Depot & SBAB

The site at the Mandai Depot has seen an increasing number of piling rigs appearing over the last few months. As works progress in full swing at the depot, the SBAB C&C has been handed over to STEC following the relocation of the airbase fence. Structural works will commence in the next quarter.

With this update we conclude the review of the existing progress of Stage 1 and 2 thus far. Our aerial updates will suspend as the haze intensifies in the coming months. We shall begin updating stage 3 towards the end of the year.

The Thomson Line groundbreaking ceremony shall take place at Woodlands this Friday.

Southern end of Mandai Depot where Orchidville once resided

The future Mandai Depot in a mock up

Mandai Depot to the left, SBAB C&C on the right

Woodlands South - It's Beginning

Continuing on from the previous update, we have a closer look at the WDS site today. The silos which were seen last month have now been hoisted up while site clearing is still in progress. The actual station box will sit beneath the existing Avenue 1/Dr 16 junction, to the bottom right of the picture.

Silos in yellow erected at WDS

Into the Woodland

As promised in this update, we will be sharing more about the area around Woodlands South. The tunnel arrangement here will be one of the most complex along the entire line due to the configuration for reception tracks to the Mandai Depot in the vicinity. As such, the authorities dedicated the entire tunnelling works for both mainline and reception tunnels between Woodlands and SBAB to a sole contract - T206. Contract T206 will further interface with another 4 contracts (T201, T203, T205 and T207)

Aerial view of Mandai Depot

Contract Award - T210, T203, T209 & T210

4 contracts have been awarded this month, on 18 October 2013. These consist of 3 stations and 1 contract to build the depot. Of the 3 stations, 1 contract is a build-only contract while the remaining 2 contracts involve design work in addition to construction. The contract awards are as follows:

T201 - Mandai Depot - Jurong Primewide

T203 - Woodlands station - GS Engineering & Construction

T209 - Lentor station - China Railway No. 5 Engineering

T210 - Mayflower station - Gammon Construction

An interior view of the paid transfer from the NSL platform at Woodlands

A new exit to be built at Woodlands

To date 7 contracts for TSL1 & TSL2 have been awarded. The remaining three include T213 (Caldecott - Samsung C&T), T206 (Tunnels between Woodlands station & Woodlands Ave 12 - Shanghai Tunnel) & T205 (Woodlands South - Woh Hup).