How is the North East Line powered Differently?

An Alstom Metropolis C751C train stabling at Sengkang Depot.

Last Sunday (Mar 28), train services between Punggol and Serangoon stations on the North East Line (NEL) were disrupted due to a power fault at Buangkok station. But how is the North East Line powered differently compared to other MRT lines in Singapore?


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MRT trains are powered using Electricity

A Current Collector Device (CCD) fitted on the Kawasaki-CRRC Sifang C151C train.

A Current Collector Device (CCD) fitted on the Kawasaki-CRRC Sifang C151C train.

All 6 MRT lines in Singapore provide power to MRT trains using electricity and not through other forms of fuel such as steam or diesel.

Commonly used across the world, the majority of our MRT lines utilise a 750-volts Direct Current (DC) power rail, which is better known as the third rail to power each MRT train.

This third rail is located on the tracks beside the running rails and transmits power to the Current Collector Device (CCD), which is located just beside the train’s wheels shown in the picture above (in orange).

For a 6-car train on the North-South Line (NSL) and East-West Line (EWL), there would be a total of 24 CCDs – equivalent to 4 CCDs on each train carriage.


Overhead Catenary System on the NEL

A pantograph on the Alstom Metropolis C751A train to receive power from the Overhead Catenary System

Picture for Demonstration: A Pantograph Device on an Alstom Metropolis C751A train. (Train Model: Joey Foo)

The North East Line (NEL) is the only[1] MRT line in Singapore that utilises the Overhead Catenary System (OCS) instead of the third rail system to provide power to the trains.


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Just like its name, the OCS is installed overhead – on the ceiling of the tunnels, unlike the third rail.

For a 6-car train on the NEL, there is a singular Pantograph Device located on the roof of the 2nd and 5th train carriage, to receive 1,500-volts DC from the OCS, shown in the picture above.

Click to learn more about the North East Line (NEL) »


Third Rail from Now On?

A Circle Line (CCL) tunnel with tunnel lights turned on and third rail fitted.

A Circle Line (CCL) tunnel with the third rail fitted.

Currently, all MRT lines built after the North East Line (NEL) do not utilise the Overhead Catenary System (OCS) but utilise the third rail to power its trains instead.

A good example is the Circle Line (CCL) where it features a very similar train rolling stock with the Alstom Metropolis C830/C trains, but it is powered using the conventional third rail.

But that does not necessarily imply that the NEL being the only MRT line using the OCS is a bad thing, as the NEL was built to run at much higher speeds compared to the CCL.

Click to learn more about the Circle Line (CCL) »


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Insulator Replacement Works

SBS Transit had mentioned in their press release that this power fault was similar to the one which occurred in Feb 2020. Following that, they decided to replace all 112 insulators to a singular pieced design from a ‘two-piece’ one by Sep 2021.

Moreover, this insulation replacement project had been delayed due to COVID-19 and replacement works could only commence from Sep 2020 onwards. Hence, it was just very unfortunate for a similar power-related fault to occur again.

In response to the incident last Sunday, SBS Transit mentioned that they would be accelerating replacement works and will target completion by Jun 2021.

Fingers-crossed that once the insulators are replaced with the new design, such incidents would be less of an occurrence on the NEL. 🤞🏻


Related Links
North East Line – SGTrains
Circle Line – SGTrains
Network – SGTrains

External Links
Train Service at Several Stations on North East Line Disrupted by Power Fault – SBS Transit
Train Service has resumed on North East Line – SBS Transit
Train services resume between Serangoon and Punggol on North East Line after 3-hour disruption – The Straits Times
NEL train service disruption: 6 other power-related faults over the years – The Straits Times

Footnote
[1] – At time of posting


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Loh

I'm a train enthusiast who is broadly interested in the different means of technology which powers Singapore's train network.