For a trip to the Night Safari can be done 2 ways.
Method 1: you go to it by BTS down at Ang Mo Kio station (NS16) walked out the exit B and continue by bus 138 (Terminal bus is located opposite the BTS station)
Method 2: you go to it by BTS down at Choa Chu Kang station (BP1/NS4) and walked out the exit C then connect the bus line 927.