In five years time they add Dover, Singapore Expo, Changi Airport, and the brand new NEL nort-east (purple) line, hence additional terminating stations (3), (6), and (7). Going overseas has more alternative to take MRT to Changi Airport or Harbourfront.
Later on year 2009-2010 Pioneer and Joo Koon extension was made after Boon Lay station, and also the newest Circle line (orange) connecting the NEL and MRT in some stations as shown below.
It starts with full steam from 22/10/1983 with S$5 billion to bet. First 22 red stations were opened on March 1988, followed by 21 more stations on green line on July 1990. This was two years ahead of the schedule.
So lesson learned for Jakarta: we need to start with BIG! lumpsum of money, commitment, and smart and hard work to establish similar mass transport system in the capital.