Amulti-year programme to renew the North-South and East-West MRT lines - Singapore's oldest and most heavily used - will cost more than $2.5 billion. The renewal programme began in 2013, and is expected to be completed by 2024. The second phase of the programme, which is under way, involves replacing the power supply system, track circuits and first-generation trains. In the first phase, the rail sleepers, third rail and signalling system of the two lines, which opened more than 30 years ago, were replaced. A major challenge in terms of complexity is the power supply system renewal, which is to be done by 2023 and entails replacing 1,300km of electrical cables, 206 transformers, 172 switchboards and equipment in 171 substations. It also involves laying 250km of fibre-optic cables for real-time monitoring of the two rail lines.

The scale of this effort underlines the critical importance of the MRT network to the transport infrastructure of a competitive and liveable Singapore. Since its inception in 1987, the train system has come to be identified with public transport mobility in a way that buses were in a simpler age. Now, more than 130 stations across five MRT lines span the island. This 200km system has a daily ridership of over three million. Complementing the rail system are two Light Rapid Transit systems. The MRT's centrality in the public transport infrastructure is an everyday fact of life.