Looping the loops
Help is coming for the Sengkang Punggol LRT. But will it be enough?
It sure needs it. According to SBS Transit’s financial results for the first half of 2023, the LRT may have been the busiest it’s ever been, at 157k daily passengers on average. This may be due to BTO completions in the area over the past three years, resulting in growth outweighing the overall loss in demand from recent trends such as companies going permanently to flexi-work.
As asset owner under the NRFF, the LTA has announced a slew of system upgrades, including the purchase of two-car trains to completely replace the entire first-generation fleet — including the 16 vehicles that were modified to be able to work in 2-car pairs. This may be enough, or it may not be enough. We’ll see.
A hard-learnt lesson
Interestingly, in 1998 when plans for the Punggol LRT were first finalized, the projections were that the Sengkang and Punggol LRT systems combined would have 150k passengers. Guess what, we’ve just hit those projections. It took a while to get here, but that’s really more of the story of the development of Sengkang and Punggol at large.
In any case, the greater development of both new towns has also gone according to plan as well. The HDB’s annual report for FY2021/22 shows that Sengkang and Punggol have nearly 140k flats completed, out of a projected estimate of 192k. These, in total, house a population of nearly 373k. That means there’s still quite a lot more to go, and already the transport situation isn’t that great. They have had to throw more and more trips at the system in order to cope.
With about 25% more development to go, one could scale up this number and find that the public transport in these new towns could easily serve close to half a million residents. Of course, at the time, perhaps the new towns may have been designed for a higher rate of car utilization and a lower public transport mode share, all the more so considering that there was plenty of hand-wringing about LRT ridership back them.
So my question to the LTA back then was, why regress on technical specifications, especially if they knew the system had to grow? We are fortunate that we do have the platform space to lengthen the trains, unlike on the heavy rail lines. If you’ve already done that futureproofing, why not finish the job?
Much maligned as it may be, the Bukit Panjang LRT got something right when its systems were 2-car ready from day one, and a mix of 1-car and 2-car trains were operated. When the LTA needed to do capacity expansion there, all it had to do was buy extra trains — even if today, diminishing returns may mean other system optimization steps have to be taken to increase capacity there.
In contrast, we have seen two rounds of capacity expansion work taken on the SPLRT to increase its carrying capacity. First, there was a need to modify all stations and move stopping points so that 2-car trains could use the entire platform length. Previously, they stopped in the middle. Then, of course, vehicles had to be modified for 2-car operation and a new batch built so that the same frequency could be operated.
Greater than the sum of its parts
Now, we see the second round — the purchase of proper 2-car fixed units and a depot extension to allow us to store and maintain them. Considering that a whole new workshop has to be built as part of the depot expansion, this all means a very specific thing, and here’s what I think it could be.
Why are 2-car fixed units better than 2-car trains made up of multiple single cars? It sounds like semantics, but it’s actually a real benefit. I think I should go into depth on what the new trains mean, given that the last time I only made a summary.
Paint job aside, as we can see in this picture there are some other immediate differences between this two-car train and a pair of two coupled single-car trains. Most notably, the inner ends seem to be straight with a rectangular window, indicating that these vehicles are meant to always work together.
It also helps that I can point to a model which already exists — at Miami Airport. We can very likely assume that we will be getting a very similar model to Miami Airport and Atlanta’s landside people mover, both of which have a similar two-car configuration. Datasheets from Mitsubishi back this up too.
One might note that especially in Miami, the outside end of the vehicle is pretty much the same as our SPLRT vehicle. But the inside end is different — here, there is an emergency door between vehicles, and equipment cabinets more similar to our MRT lines. It remains to be seen if Mitsubishi will expand this into a full gangway, as I posited before. According to the datasheet, the model in Miami does, but the model in Atlanta doesn’t. Plus, even if there is a gangway, will it be possible to ride inside, as we see in the heavy rail lines. Or will it just be a wall like in Macau.
But what also makes this a better deal is the lack of a need to duplicate equipment, unlike what would be necessary with double 1-car trains. As we can see, each upgraded 1-car unit has to have two of these boxes, one at each side of the train. This means that a modified single train car would thus have 4 seats lesser than an unmodified car, even if standing space largely remains the same.
Like the unmodified cars, 2-car sets would allow the equipment to also be placed inside the full-height equipment cabinets on the inner ends of the train cars. And if we assume that each cabinet is a redundant copy of the other (in the name of system reliability) and two cabinets are needed per train, we can even spread out the two cabinets across both cars, since one cannot function without the other anyway.
That ultimately means more space for passengers. At the very least, we can be able to regain the space lost when refitting the now-modified cars. A better scenario, which I think likely to happen, would be if the passenger cabin is able to be expanded somewhat into the significant dead space between cars. There could be more standing space, more seats, or both.
Space for optimization
These 2-car sets alone can help, but won’t necessarily help the situation that much. Ideally, they should come with additional features to help the passenger experience. For one, on the trains themselves, additional displays that also show the vehicle route can be placed. This can take the form of LCD route maps as we see on newer MRT and LRT vehicles. It can even be similar to Taipei, where LED lights on the outside of the vehicle indicate whether it’s going east or west.
This may not be so important considering the big signs at the Town Centre stations indicating which loop one is on. But those big signs are only at one point of the platform, and aren’t that visible to people waiting nearer to the train. So with longer 2-car trains, better train route information has to be presented for people up and down the platforms.
And these trains can hopefully also have more motor power for better acceleration, to mitigate the impact of low-speed zones in the shared sections of the network. I don’t expect it to be as good as the French — French rubber-tyred metros rocket out of stations — but perhaps some improvements over the current state can be considered, especially as it appears even NEL trains can accelerate faster than the LRT vehicles.
Lastly, as part of the enabling works for network-wide 2-car trains, it really is time to modernize the communications systems, especially with next train arrival. Knowing in which order the next train arrives can help; this uses the effect of loops where it can be faster to go the long way around rather than to wait for the next train going the right way. All the more so, since anecdotally there are stories I’ve heard where multiple trains going one loop can arrive before a train on the other loop. Good data can allow people to just take the first train they see, instead of waiting on the platform and causing platform congestion.
Paths not taken
But as I’ve said, what I find more regrettable is that there are further paths not taken. Sure, the LRT depot expansion costs a lot already. And we can’t even say it’s avoidable considering that we are fundamentally overhauling the definition of an SPLRT train, and we would thus need new facilities anyway.
For starters, the growth of the fleet is not actually linear. We are purchasing 25 new two-car trains. But these will actually replace 41 single-car trains, so at the end of the day, the overall increase in the fleet is only 9 cars. Is it worth tripling the size of the depot for only 9 extra cars? I personally doubt so, even if an argument can be made that much of the depot expansion space is dedicated to tracks to move around the depot. Whilst some might argue that part of the 41 cars original order may have been for the cancelled Punggol North line, that doesn’t mean it’s not worth having more 2–car trains.
Perhaps the next capacity expansion step might be a rationalization of the maintenance facilities to facilitate the storage of additional trains, and the purchase of those extra trains. Facilities previously provided in the older section, such as parts of the old maintenance building, and which have been replaced in the newer sections, can potentially be modified and used as train storage.
Likewise, the strategy for storing trains along the Punggol side of the network can also be reconsidered, with trains being stored at platforms more often. If we’re open to this, it could allow us to purchase more trains that can fit into the depot. But can we put them to good use, though?
Controls, controls, controls
From a policy perspective it’s easy for me to say that we should consider modernizing the train control system as well. Considering that one attempt all but blew up in our faces, and the other seems considerably delayed from initial timeframes, this may be a harder risk to take.
But what are the problems we’re trying to solve? For one, the sectors around the Sengkang and Punggol Town Centre stations are extremely slow, and perhaps finding a way to speed this up may be welcome. When it takes 3 minutes to travel 1km, a consistent experience across all eight LRT services, something is quite wrong. After all, unlike BPLRT vehicles, the SPLRT vehicles are faster than buses. On several intervals within the loops they can and do go faster than 60kph; but this obviously doesn’t result in overall travel time improvements due to low speed limits within the shared sections.
That said, if the existing fixed-block train control system can be optimized, perhaps it’s worth considering how to optimize it. Perhaps block lengths can be shortened to permit higher speeds. Perhaps, even, we could find a more robust switch design to allow trains to cross a switch area at more than 10–15kph. Mitsubishi apparently has a design out for what they call a “High-Speed AGT” — it would be nice if some track and train technology from this could be adapted for the SPLRT.
Changing the train control system is a big ask, but it may be necessary to facilitate some of the control system changes we need to make, if the above is not enough. I’m not sure whether something as disruptive as moving to moving-block CBTC may be needed to fix these, but it might well be. That is disruptive work, and I can understand if they want to put it off for as long as they can.
But if they do, it may be timely for some bigger interventions as well. The Sengkang LRT side can, in theory, be upgraded for 4-car operations. Yes, that was not a typo! 4-car trains can be reasonably put together from a pair of 2-car trains. This will involve concrete, such as to move away some plantrooms at some LRT stations, but a majority of stations including Sengkang Town Centre are ready for it.
Or, perhaps, a new train control system could allow two trains in a station at once. It’s safer than it sounds — San Francisco is doing it — and in our case, separate boarding points for East and West Loops could even be set up at Sengkang Town Centre. Platforms are long enough, anyway, especially now that a new stretch of platform has been built at the south end of the platform as part of station expansion works. It’s more than enough for 4-car trains, so you could likely even have two trains stop inside the station with a safety buffer between them.
Like this, a second train could be allowed to enter the station while the first train is boarding. This is similar to some very busy bus stops that are designed to be long enough for multiple buses; and like at the bus stops can help increase throughput through the station. With separate stopping positions for East and West Loops, it might even help make the Sengkang LRT easier to use.
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