Many Singaporeans rely on public transport daily, but do you know which is the oldest train line in Singapore? We hit the streets to find out if people know the answer. Singapore's MRT system began in 1987 with just five stations on the North-South Line (NSL), linking Yio Chu Kang to Toa Payoh. Though modest at first, the NSL was the foundation of Singapore's vision for a seamless and integrated transport network.