The original four,
Silver Link, Quicksilver, Sliver King and
Silver Fox were intended for the
Silver Jubilee express, a once-a-day service from Newcastle to King's Cross and return, introduced in the same year as King George V's silver jubilee. The next four,
Golden Fleece, Golden Shuttle, Golden Eagle and
Golden Plover were standard LNER apple green, intended for the
West Riding Limited from Bradford and Leeds to King's Cross and return. They also introduced a batch of "general service" A4s with bird names, intended to run alongside the A1s and A3s, allowing the last Atlantics to be phased out. These worked the
Flying Scotsman as well.
Later, the regulator of the day relaxed the restrictions on train times between London and Scotland, allowing the LNER to introduce the
Coronation express between King's Cross and Edinburgh (in the year of King George VI's coronation). The five A4s intended for this all had Imperial names,
Empire of India, Union of South Africa, Dominion of Canada, Commonwealth of Australia and
Dominion of New Zealand. For this, they introduced the new garter blue livery, with garter and Marlborough blue for coaches. Pretty soon, it spread to the other A4s as well, including the silver ones. Partly, this was because the apple green paint tended to flake off the smokebox sides because of the heat. The A4s yet to be built, originally with bird names, but later usurped by company directors, were also painted garter blue from the start.
Plenty of good information
here.
