KLM did not drop Rangoon in 1957, but operated to the Birmese capital well into the jet age.
The last routing was
AMS-
KHI-
RGN-
HKG on DC8-50s in 1978.
The KLM route AMS-HKG route was the last route to see DC8 aircraft, as the UK-NL bilateral at that time deliberately restricted KLM to 1x weekly DC8 service in order to reduce competition on the British domestic route UK-HKG. The route operated AMS-KWI-KHI-RGN-HKG for many years.
The route was dropped when KLM substituted DC8's to Asia with widebody B742 and DC10 aircraft, as
RGN 's runway was unfit to handle the heavier aircraft.
[Edited 2015-05-14 23:49:00]
On the liberalisation of the UK-NL bilateral in the 1980s - the first European Open Skies - KLM was able to increase AMS-HKG to widebodies and a higher frequency.[Edited 2015-05-14 23:51:04]