We’ve been waiting for this a while now.

Yes, it’s been quite a long wait, and with this announcement comes some much needed respite for people who live in the west (like me), who’ve had to watch as east siders get a whole slew of new lines like DTL3 and TEL, but we still have to pack ourselves into rush hour trains at Jurong East every day to get to work downtown.

Here’s the ST article on the matter, if you’ve been living under a rock and don’t know what I’m talking about:

With the weekend, I thought I’d sit down to take a look at how this rather interesting line may operate. This will be quite a long post, so please bear with me.

No, not like the Russians

The JRL is the first line in our MRT to run a relatively complex branching operation due to its unique layout, with two branches on each end and a central core through Tengah.

Why is this different? On a branching system, one has two choices. Either a shuttle train can be operated on the branch alone, forcing a transfer back to the main line (like on the Changi Airport branch of the EWL), or trains can be operated all the way from one end to the other, alternating branches (like how the Circle Line operates in the peak hour). The former introduces a degree of inconvenience to passengers, while the latter complicates the train service.

This is because a strong emphasis on punctuality is needed for trains approaching from one of the branch lines, so as to make its “slot” to enter the main trunk section. This also theoretically limits the highest amount of trains that can run on the line, due to all the waiting that must occur if trains are not punctual. And I believe many here don’t have that confidence in the railways.

A while back I wrote about how the Russians manage to run 40 trains per hour on the Moscow Metro — avoiding branching is one of their solutions. The only line with an alternating branch system, the Filyovskaya Line, has a low enough ridership to justify it anyway.

Ring around the rosy

LTA has interestingly chosen to take a third option here, by adopting a round-robin service where trains start from Choa Chu Kang, then go to the Jurong Hill and NTU branches, then back to Choa Chu Kang. Interestingly, no service is provided in the opposite direction. This effectively eliminates all the branching issues mentioned above, which on paper will allow as many trains as possible to be run on the line.

Screencap from LTA’s JRL publicity video (source: LTA)

Breaking it down, here’s what passengers will be expected to do when the JRL fully opens:

Stay on the train:

Choa Chu Kang to Jurong Hill

Jurong Hill to NTU

NTU to Choa Chu Kang

Alight at Bahar Junction and change:

Choa Chu Kang to NTU (1)

NTU to Jurong Hill (2)

Jurong Hill to Choa Chu Kang (1)

Alight at Tengah and change:

Anywhere towards Jurong East/Pandan Reservoir/West Coast (in future?)

Jurong East/Pandan Reservoir/West Coast to other parts of the JRL

But there’s always a catch, and here it is. LTA’s official map for Bahar Junction seems to show two considerably separate stations connected by a linkway, which I estimate will be about 80m-100m long. Notice the (1) and (2) that I put in the previous list? The sole (2) transfer will be a cross-platform interchange, but transfer directions labelled (1) will require you to take the linkway, or alternatively to go ahead to the next station (Boon Lay and Gek Poh respectively) where a cross platform interchange can be provided.

One thing I can forsee is that every user of the JRL will have to change trains at least once, potentially creating a bottleneck at Bahar Junction and perhaps at Tengah too. Consequently, could we see an expensive station modification down the road to increase the capacity of Bahar Junction station, or provide more paths for trains? Who knows.

An alternative would be to reverse-signal the line so that trains can run in the peak direction, reducing the amount of transfers most have to make. This was done before with the Punggol LRT, however I will admit that it is confusing, with trains going in different directions at different times of the day. Perhaps we may start needing to pay attention and not just keep our heads down on our phones and such.

Khaw’s new roller-coaster

Another interesting thing about the JRL is that it will use trains with smaller cars, which at 18.6m by 2.75m are roughly comparable to NYC’s R160 vehicles. As the JRL will pass through already built-up areas like the BPLRT, apparently smaller vehicles are needed so as to be able to make tighter turns around already-existing buildings.

Yes, this means that the JRL ride experience will be very similar to the BPLRT, and we know what our transport minister has said about that. A key difference is that the JRL will not use the single power/signal rail as on the BPLRT, that’s repeatedly been cited as a weak point of the BPLRT system— in fact, it is planned to be built as a regular, MRT-specification third rail system. Apart from the sharp turns and high gradients of course.

In this aspect I would say that it’s more similar to the LRT systems of our northern neighbours in KL, which are “light” only in the design of the vehicles used. The Ampang and Sri Petaling lines even use 6-car trains, which I predict can carry about the same as a 4-car JRL train. It’s also important to remember that like the Circle and Downtown lines, the JRL also first appeared in the 2001 Concept Plan as a light rail system.

“When one tires of London”

Observers may note that the JRL also has a very similar geography to the initial sections of the Docklands Light Railway in London, as well as a very similar purpose and design. The DLR was built as part of the redevelopment plans for Canary Wharf and the Docklands, which is very similar to what URA has in store for the Jurong Lake District.

Map of the DLR (notice anything similar?) (Source: Transport for London)

However, the DLR prefers to adopt a more traditional branching method of traffic as opposed to the round robin way that will be in operation on the JRL. This is because the DLR serves multiple centres of activity, including Canary Wharf, London City Airport, as well as the transport hubs of Stratford and Bank. To achieve this, it has multiple services from each of the various termini.

The same can arguably be said about the JRL, though. Choa Chu Kang as a major interchange from the north, Jurong East, Tengah, NTU, so on. Hence, I’m personally not sure whether the round robin mode of operation will be sustainable in future when the Jurong Lake District is more developed and there’s an increased need to get around within the Jurong region.

If it were up to me…

Of course, no blog post from me would be complete without the “if it were up to me, I would do things this way” corner.

So if it were up to me, I’d simplify the JRL. Firstly, I’d built a turnback platform (and perhaps a third track) from Bahar Junction to Boon Lay, and in the initial days have a shuttle running between Boon Lay and NTU (brown arrows). Eventually, trains would run from NTU, through Hong Kah, to the Jurong branch (red arrows). And likewise, a second service from Choa Chu Kang to Jurong Hill (black arrows).

An additional platform could also be built at Tengah Central for short-turn trains on the Jurong East branch, between West Coast and Tengah Central only (which is how LTA proposes to operate the Jurong East branch anyway, shown by the blue and white line). Or they can go to Choa Chu Kang as well (green arrows).

Shitty MSPaint work by me again

While this approach would still force a certain segment of riders to make one transfer or more, and reduce the potential throughput of the JRL by introducing a merging operation, I think it’s a better compromise between both frequency and passenger convenience.