Baking the lime green pie

From the Red Line
Published in
10 min readApr 20, 2024

Looking at the scale of our rail expansion projects.

Editor’s note: You may have seen an earlier draft of this post on Monday, when I accidentally hit “submit”. I’ve rescheduled this after making some edits, and it should go out as per the usual Saturday schedule.

We saw one case being the intricate link between the East Coast Depot, TEL5, DTL3 Extension, and the new tracks and platforms near Tanah Merah station. What is supposedly a localised issue with construction around Xilin station has likely snowballed into the entire project being kicked back to 2026.

But could there be more? Third-party estimates from 2016 show that the CRL may cost up to $40 billion. But we don’t really have an improved estimate, since MOT’s Budget Book for 2024 throws all rail expansion projects under a single earmark — a change from the previous ministry where individual projects (NEL, every stage of CCL, DTL, TSL, ERL) each had their own earmarks.

Cost control

The LTA may be attempting to greenwash some of its cost cutting measures, but I see no reason why they shouldn’t be straightforward about it; more cost effective design and implementation means more people benefit from MRT service, and earlier. To be fair, Singaporeans may misunderstand that; but perhaps the LTA can open up to academic study where they can at least look through the final report and clarify any ambiguities before publication.

NYU’s Transit Costs Project having to use newspaper estimates means that they can’t even apply their methodology consistently; and they’re thus forced to make very unflattering comparisons that don’t describe Singapore’s reality. Same goes for the New York MTA; when they made a whole slide deck attempting to justify the Second Avenue Subway, we also didn’t get a very good look out of it.

source NY MTA

In Budget 2024, the LTA had an earmark of $75 billion for rail expansion — significantly reduced from Budget 2023’s earmark of $96 billion. However, on MOT’s end, a similar earmark for rail expansion increased from $24 billion to $30 billion. Still, a $15 billion saving is nothing to scoff at; with that money, we could very well finance the 9th MRT line from Sengkang West to the CBD at least. Then again, while we don’t know if the savings come from completed projects being closed out, and/or planned projects getting cancelled or descoped, or funds to be provided by SINGA, the total sum spent so far has not decreased accordingly.


The LTA choosing to go for the first of the three Rs — “Reduce”, in this case, may be a source of cost control too. Reduced material use may come from optimizing space inside stations, meaning that smaller stations need to be built. While many CRL stations will still have the underpass levels and such we’ve come to see on the TEL (even at open-cut areas like Tampines North), there can still be savings made here.

I won’t be surprised too if significant changes to reduce costs were also an effect of CRL2 environmental mitigations — perhaps this might explain the big diversion in the CRL2 environmentally-mitigated alignment compared to what was originally planned. Perhaps there may be other ways of construction, avoiding the need to cast extremely deep retaining walls to support a large open excavation which is eventually backfilled anyway. After all, CRL Hougang is also around 42m deep (according to the Project Information Centre) because it needs to go under the underground NEL; we can presumably see the same at King Albert Park.

Original alignment in red, mitigated in blue (source CRL2 EIA)

There is definitely a case for reducing excavation — the CRL2 EIA says that a whopping 1.4 million cubic metres total will need to be excavated for the CR14 and CR15 stations, compared to only 300k cubic metres for CR16 station. Whatever is done, we will only know when the CRL2 station designs are finalised by the appointed contractors, and/or the Project Information Centre opens to the public. I don’t expect this to happen before 2025, especially since several contracts haven’t yet been awarded at the time of writing.

Though we already have an example — designs for CR11 Ang Mo Kio station were modified to avoid digging under existing MRT viaducts; it wouldn’t surprise me if this was made possible by optimizing space within the station to reduce the station’s overall size.


War-on-cars types may cheer the North-South Expressway being delayed to 2029 — at least, the tunneled bit that really matters between Lentor Avenue and Bugis. But I think this is related to the complexity around Teck Ghee station. It is necessary, as there must be a transfer point between the north-south bus trunk proposed with the NSE, and the east-west CRL. But like how Stevens was one of the last TEL3 stations to be completed due to the narrow workspace along Stevens Road, the vast excavation work needed for the overall station and expressway structure may mean that the expressway tunnel cannot be opened until the MRT station below has reached a point of sufficient structural readiness; which may not be until 2029.

Teck Ghee isn’t the only station where large public works are being undertaken for the CRL. Loyang station will be the first three-track underground station built in 20 years (the first being Paya Lebar CCL); and they’re also throwing in a stretch of Loyang Viaduct above the station — again necessary to increase truck capacity to Changi Airfreight Centre; much like the Tuas Viaduct and Tuas West Extension before it.

The same applies to Pasir Ris. Why does it get to lay claim to the deepest MRT station in Singapore? Not only is the Dr 1/Dr 8 junction higher than the area around the EWL station, they’re also building a four-level underground station with two levels of stacked platforms — a design similar to Shenton Way TEL, which is 38m deep. It probably doesn’t help that the area used to be mangroves dotted with sand quarries, and the station may have to be that deep for soil stability purposes around the tunnels.

source NUS Libmaps

There are also several other CRL stations with full-length underpass levels above the main concourse, namely Elias, Riviera, and Serangoon North. Aviation Park may perhaps be deeper than it should be too; but all these may be technical constraints with the bored tunnels on either end, and it raises the question on whether these spaces can be commercialized, or developed as bike parks, or all of the above.

On the JRL as well, there are design decisions I find perplexing. While most JRL stations are built directly over the road, with no road-level facilities apart from station exits unlike their EWL counterparts, there are some that also have multi-level designs yet are built on the roadside. This is unlike earlier NSL stations which have the ticket concourse on the ground level. Larger stations with more public floor space would naturally require more architectural finishes.

Pandan Reservoir, as the most egregious case, has platforms on the 4th floor, with its ticket concourse on the 3rd floor. All that’s on the second floor appears to be a void deck and a bridge connecting to the other side of Jurong Town Hall Road. Could the station have been built over the road instead, freeing up land for other purposes — or at least, could the current design be modified to permit Teban Gardens Road to connect to Jurong Town Hall Road?

A systems perspective

In its 2022/23 Annual Report, the LTA claimed that it managed to save $400 million in rolling stock costs for the CRL by various optimizations. It is not because they awarded the contract to CRRC Qingdao Sifang — though, considering the standardization of metro trains in China, it isn’t surprising that CRRC managed to pull off the lowest bid, as we’re essentially asking for Chinese Type A trains.

LTA 2022/23 Annual Report

Increasing maximum train speed should be good news for many people. Information at the CRL Project Information Centre shows that the CRL trains will have a maximum speed of 100kph, much like the TEL trains before it. When the LTA says they will increase the operational speed, I take this to mean that it is likely the CRL trains will push much closer to the speed limit than before; much like how the Kajang Line trains in KL are quoted to be able to reach 98kph, having been designed for 100kph.

A short-trip “inner loop” service also makes sense, by putting to work some of the infrastructure that will be built. I suspect one end of this inner loop will be at Loyang station, turning around using the middle track there. After all, from Loyang it’s about 10km to Changi T5’s Ground Transport Centre where the MRT platforms are likely to be. The same probably can be said for the west end; the west end of the inner loop may be a CRL3 station, if not the terminal facilities built at Jurong Lake District station for CRL2 operations. After all, it’s unlikely that airport and Jurong Industrial Estate demand will be able to support six-car trains every two minutes, much like the Tuas Extension today.

That said, buying lesser trains means more questions has to be asked. For now, the CRL train fleet is planned up to a maximum of 55 six-car trains; but Changi East Depot will be able to hold up to 70 eight-car trains, and there’s still another planned depot in the west near the Singapore Rail Test Centre. PIC displays also show sidings at Tampines North and Teck Ghee in addition to Serangoon North, and the CRL2 preliminary designs from the EIA also show sidings at Turf City and Maju stations.

Do we need so many? Were they a relic of an attempt to design Japanese-style timed overtake express services? There is a need for temporary storage space, as CRL2 will need to be supported by Changi East Depot before the completion of the western depot in Tuas. While the LTA could take some lessons from how SMRT runs TEL4 around Bayshore, perhaps much of these temporary facilities should be built near JLD station instead, where there’s plenty of space for cut and cover construction. Perhaps when designs for the CRL2 stations were finalized, where these facilities are provided may have changed.

The road ahead

In FY2020/21, the LTA awarded the contract for the engineering studies for the Downtown Line 2 Extension. Two years later, it began the engineering studies for CRL3. Similarly, the engineering studies for Brickland station began in 2020; but project details only came out last year, tendering is currently in progress, and construction will perhaps start end of this year. And of course, nothing has been heard about the JRL West Coast Extension; though I won’t be surprised if the LTA has been forced to put that on the backburner while other projects take priority.

Perhaps the LTA has had to take lessons learnt and apply them to these projects, which explains why it has taken three years for the engineering studies, as they have had to go back to the drawing board and optimize station and alignment designs. I still expect the DTL2e, at least, to be announced this year, but I could be wrong. As for CRL3, we should hear about that this year too, since the LTA claimed it takes two years for the studies to progress, and it is also taking onboard environmental protection features in the CRL3 design.

After all, the goal is to have about 360km of MRT lines by the early 2030s, which covers the expansion plans announced in the Land Transport Masterplan 2013. It may be acceptable to fall short slightly and not include the 13km of CRL3, especially if the LTA is also occupied with systems works for the MRT extensions to Changi T5, due to open in the mid-2030s.

This pause should ideally also help to improve constructability of MRT extensions; whether by streamlining designs to reduce material usage, standardizing designs and components as much as possible, or other means which the LTA engineers and consultants may find. With the area of CRL3 and DTL2e likely having relatively less infrastructure in the 20m-30m layer which MRT tunnels generally sit in within, there shouldn’t be too much to dig under, and steps to reduce depth and volume of proposed stations should be taken.

In fact, with JTC’s redevelopment of Sungei Kadut, the LTA may even be able to build very shallow stations and place faregates on street level; much like Bishan or Sengkang stations. Not only can easier projects be built faster, there are also lesser things that can go wrong, reducing the amount of risk overhead that has to be budgeted for. And like Sengkang, if they play their cards well, this can also mean a direct lift ride can be provided between the NSL and DTL platforms at Sungei Kadut station.

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From the Red Line

Sometimes I am who I am, but sometimes I am not who I am not.