From the Red Line
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From the Red Line

Do you need express service?

Pardon me if I sound a bit too cranky. Exam period just ended after all.

Also, lately I’ve been spending too much time on reddit yelling at army boys who make the trek from the west to Pasir Ris (for buses to Tekong), or from the east to Gedong (well you know). From my personal experience, I could probably talk to self righteous NSFs (or taxi/Grab uncles, maybe one morphs into the other) and find out everything that’s wrong with the country.

Rant aside, the collective circlejerk when it comes to “how would you improve the MRT” is either “express trains!” or “four tracks!” My answer, as always, is no.

Greater Greater Washington has explained why four tracks aren’t necessary in DC. The similarities between our system and theirs are aplenty, so it bears repeating and some translation into the local context. I’ve written about this before anyway, but recent conversations and the GGWash article probably merits revisiting the topic.

And given that those who read my blog are likely a self selecting bunch, if I can’t convince you, I don’t know what can. I’m not here to stroke your anti government boners after all.

A tale of two cities

While doing some research for another upcoming post, I happened to look into the case of another country with military conscription, a warmongering neighbour up north, and few express services.

The subway lines in Seoul are long, very long. Heck, Seoul Line 3 is 57km long and has 44 stations — a profile similar to our MRT lines. No express service there either. Line 4, on the other hand, actually does — but the express only skips a grand total of 9 stops out on the edges of the Ansan Line. That’s actually a fair bit considering that the entire stretch where express trains run is 25km long — a whole third of the 72km long Line 4.

This is useful in some cases, as GGWash has also pointed out. How? A cursory glance at the express section of Line 4 on Google Maps shows that the express stops along Line 4 are spaced to hit relatively major population centres, compared to the rest of the line. We do have cases like this in Singapore, such as Bayshore and Bukit Panjang. But not on the mainlines, which have a high amount of passenger traffic and stations spaced pretty far apart.

But let’s say you were a stubborn one and you wanted the LTA to do a study on introducing express trains. Well, I’m not the LTA, but I’ll give it a go. We’ll try it out of the Downtown Line, since it has relatively high catchments near its ends (Bedok/Tampines and Bukit Panjang), and as described below, the infrastructure to do so.

Playing leapfrog

There are three stations (and one “station”) on the network which are designed to allow for “overtaking” operations — meaning, to let a train pass another. These are:

  • Fort Canning
  • Mattar
  • Keppel (opening 2025, obviously)
  • Bukit Brown (no one actually knows when)
Track layout at Fort Canning, Mattar (and soon Keppel), additional crossovers omitted for clarity. Diagram made in MSPaint by me.

Note the two additional lines further out from the tracks. Officially, these are sidings that can be used to store disabled trains, but since they look somewhat familiar, maybe we can repurpose them to let express trains on the Downtown Line overtake local ones as well.

But not so fast, there’s a problem with this. Section 2.4.1.3 of the LTA’s Civil Design Criteria manual (which, for some reason, is available on the internet) states that turnouts where regular passenger trains operate must be passable at a speed of 55kph or higher. I’m not so sure at what speed they can be used now, but if you want to do this, it may be necessary to rebuild the crossover access to the siding (which means a weekend full closure like what’s happening at Canberra over the Vesak Day weekend). And since they need to work within the confines of the existing tunnel (unless you want to add even more expensive civil works?), it may not be completely doable.

But whether the crossovers to the overtaking sidings are rebuilt or not, this may mean that trains still have to slow down to traverse the siding, which negates some of the benefits of going express.

Not fast, not furious

I did a very unscientific study a while back, going back and forth between Hillview and King Albert Park stations with a stopwatch.

It takes approximately 20 seconds for a train to come to a stop from line speed (which usually is 80kph), and another 20 seconds to get back to line speed. In the case of Beauty World station, trains are programmed to stop for around 30 seconds, from wheel stop to wheel start (so subtracting door open and close times, about 25 seconds to exchange passengers). That’s a total of 70 seconds.

Using the site of Hume station to estimate how long it takes for a train to pass a station precinct without stopping, I got about 15 seconds (we can add a bit more since trains would have to slow down to use the overtaking sidings). Hence, I think it’s fair to say that each skipped station only saves you about 45 seconds a station. So with an express service that makes no stops between Chinatown and MacPherson, you’d save about 5 minutes. That is, of course, if you wait for the express that comes every 4 minutes, or every other train — this gap lessens to an average of 3 minutes if you run every third train express, but express waiting times increase to 6 minutes.

At the end of the day, you’d save only about a grand total of 3 minutes on average — a percentage that decreases the further you go. Is that worth a couple tens of millions in crossover replacement and increased waiting times for people who live and work near stations in between?

Stand up and be counted

Ridership numbers for Fort Canning through Mattar in March 2019 — entries in the left column, exits in the right

Here are the ridership numbers for the skipped stations in our test express route. They’re not bad, but along the DTL there are worse performers (like Upper Changi and Cashew), and these are definitely lower than the stations east of MacPherson.

That’s not to say that it isn’t worth a try, since the infrastructure is mostly there. At the same time, it’s interesting to note that a considerable amount of folks actually go the other way to Tampines station and take the EWL from there. Would such an express service convince them to take the DTL instead?

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yuuka

yuuka

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