[7][8] After deciding on a rail-based system, the construction of Phase I of the MRT system,[9] which will be the North–South Line, was given priority as the line passes through areas having a higher demand for public transport, such as the densely populated housing estates of Toa Payoh and Ang Mo Kio and the Central Area.

If the people and the Government continue to work together, as we have done in the past, we will produce the economic growth and budget surpluses to build, not just a world-class transport system, but also the most attractive Singapore for our children to grow up in the 21st Century.

[21][22][23] Numerous changes were made to the number of stations for the extension mainly to accommodate the 1991 Concept Plan by the Urban Redevelopment Authority,[24] which aimed to make Woodlands a regional centre for northern Singapore.

There was also a need to level the land covered in thick vegetation in Kadut, Woodlands and Sembawang for the MRT line.

[33] Under the Land Transport Master Plan 2008, the Jurong East Modification Project entailed the construction of a new platform and the addition of a fourth track to Jurong East station to reduce waiting times and crowding at the station during peak hours.

[40] On 17 January 2013, the Land Transport Authority (LTA) announced that a feasibility study was conducted to construct Canberra MRT station.

The station cost S$90 million to build,[45] and is meant to serve upcoming developments at the vicinity.

[46] On 3 March 2003, a 23-year-old man lost control of his vehicle along Lentor Avenue, crashed through the fence, and landed on a stretch of track between Yio Chu Kang and Khatib stations.

The incident forced a train carrying hundreds of commuters to come to a screeching halt, but not before flattening the front of the car.

The accident disrupted train services for more than three hours and cost SMRT between S$100,000 and $150,000 in damages and lost revenue.

[47] On 15 December 2011, train services between Bishan and Marina Bay stations were disrupted due to damage sustained on the power rail between City Hall and Dhoby Ghaut.

[48][49] Two days later, a similar problem caused a seven-hour disruption between Ang Mo Kio and Marina Bay.

[59] Although no injuries or casualties were reported, SMRT fired a total of eight employees from the maintenance crew, and incurred a S$2 million fine, following the incident.

[62] The incident led to a replacement of 150km of power cables for the Tuas West Extension and two SMRT staff being suspended.

This resulted in train services to be suspended between Choa Chu Kang and Woodlands stations for more than two hours.

[64] In the Land Transport Master Plan 2040 (LTMP2040), two new infill stations are projected to be built along the existing North–South Line.

[69] Each day, the first train begins service at the following timings: Extra downroute trips were added to start from Newton, Bishan and Kranji to cater to the demand.

[71] Additionally, short-working trips do run from Yishun to Marina South Pier, which only operate during peak hours.

[73][74] The North–South line forms an incomplete loop from Jurong East in the West Region of Singapore, north to Woodlands and Sembawang, and south to the Central Area.

[85] After Sembawang station, the line follows the route of Canberra Link and Yishun Avenue 2, curving southwards.

Legend List Electric Multiple Unit (EMU) trains on the North–South Line operate in a six-car formation, based out of Bishan Depot and Ulu Pandan Depot, which provide train maintenance, inspection and overhaul facilities.

[101][102][103] The C151A trains were the first successful joint venture between Kawasaki Heavy Industries and CSR Qingdao Sifang in the international market.

[104] As part of efforts to further increase passenger capacity on the line, newer C151B and C151C trains were subsequently delivered in 2017 and 2018 respectively.

[96] When the line was first opened, full-height platform screen doors supplied by Westinghouse were installed at underground stations.

[125] Nevertheless, the LTA reversed its decision and made plans to install half-height platform screen doors on elevated stations on 25 January 2008.

[126][127] The first platform screen doors by ST Electronics were installed at Pasir Ris, Jurong East and Yishun stations in 2009 as trial runs.

[129] The NSL was built with wooden sleepers, which needed to be replaced when they neared the end of their lifespan of 15 to 25 years.

The replacement sleepers, made out of concrete, have a significantly longer lifespan and enable smoother and safer rides.

[130] Since 2014, train services on the line have ended earlier for critical maintenance works, with the exception of a break between September 2016 and December 2016.

However, constant contact between the train's Current Collector Devices (CCD) and the line saw the need for replacement works on the third rail, which were completed in August 2017.