Note: All the length specified in this section, including in the following leading paragraph, is only nominal. An Olympian 11m is not, and never exactly 11000mm long but some 11300mm.
Initially, KMB used a system which usually used the first letter of the bus manufacturer to code their fleet.
D - Daimler buses
L - Leyland buses
Second-hand classic age
In the 1970s, the British makers were unable to cope with the vast demand of clients around the British world, so operators like KMB resorted to purchasing second-hand buses and these were numbered with 2 before the alpha code to differentiate them.
2D - second hand Daimler buses
2L - second hand Leyland buses
Age of 3-axle buses
With the introduction of the longer 3-axled buses, KMB added 3 to the numbering and S was further added at the front for 11m buses to emphasize that is a short variant (under 12 metres).
3N - Dennis Dragon 12m (1982-2003)
S3N - Dennis Dragon 11m (1986-)
List of the fleet codes of the non-A/C buses in service recently