SBS first introduced aircon buses on partial fleet of sv 168 in
1980s. Then introduced aircon 3 and aircon 118 in 1987.
In 1989, SBS re-routed sv 13 to YCK from Ghim Moh and converted
into aircon service, then also introduced aircon 76.
In 1990, M1 and M2 were also converted to aircon services.
Tibs had also introduced its first aircon sv 950 somewhere in 1989,
followed by 951, 952, 825 and 857...
All these as far as I know, feel free 2 add on more ideas/comments
