Isochronic Singapore: Hypothetical Line Failures

As mentioned in the 2013 Land Transport Master Plan, Singapore’s metropolitan rail network continues to form the “backbone of our land transport system.” Compounded with a supporting bus network that is traditionally based on a hub-and-spoke model anchored around metro stations (with the exception of the newer Circle Line and Downtown Line), we started to wonder what would be the affect on commuters if, hypothetically, each of the major metro lines were to experience a failure or disruption.

Previously we have assessed the reach and impact of the Downtown Line failure, applying the same technique for assessing the reach of a line failure, we can then get a shape and sense of which areas are affected by the various hypothetical line failures, and thus which areas are more vulnerable to these failures.

In this case, we will be focusing on the reach of each of these hypothetical line failures.

As with the analysis on the Downtown Line failure, we will once again employ our toy accessibility index, the Hawker Centre Accessibility Index to measure the loss in mobility and accessibility.

Once again, the Hawker Centre Accessibility Index measures mobility by looking at the number of hawker centres accessible from a starting point within an hour on public transport.

It is worth noting that the Hawker Centre Accessibility Index is weighted towards the city core, which also implies that the loss in mobility is weighted towards commutes travelling towards or away from the city core.

As mentioned in the analysis on the Downtown Line failure, depending on the availability of alternate transport routes during a disruption or failure, the impact on an area might be amplified or dampened.


It’s no surprise that the bulk of the effects of any hypothetical line failure would be experienced along areas serviced by that line, with a growing effect the further we are down the line. Though there are certain areas that seem more vulnerable.

Notable are the areas around Bukit Batok, Bukit Gombak, Choa Chu Kang and Yew Tee stations in the west. Which are vulnerable to both failures on the North-South Line and East-West Line.

Along the North-East Line, probably due to the way the new towns are planned, any station further up the line after Kovan station would suffer substantially from a North-East Line failure.


Quoting Alan Pisarski, “[m]obility, which I would argue is the centerpiece of our national productivity”. Considering our nation state’s emphasis on productivity, it would be ideal if the backbone of our land transport system was completely reliable and faced neither delays nor disruptions.

But disruptions and delays happen.

And the value of being able to see the shape of disruptions would be the ability to plan for and decide how relief services could take form and shape. Seeing that the current routing of bus services provide inadequate relief during a disruption, especially to vulnerable areas as mentioned above, or in areas further down the lines. As such, the suggestion is to have relief buses ferry commuters directly to a well connected areas within or nearer to these areas and let the local bus services take over from there. And these relief routes would have to differ depending on which line fails.

Read more about the Hawker Centre Accessibility Index here.

And if you haven’t, you should check out the write-up on isochrone maps that led to this analysis.

Originally published at