In 1841 mail contractors in Western Australia began a monthly mail delivery from Albany to Perth by horse and spring cart. Mail routes also began to expand from Adelaide to the newly developing South Australian settlements at Port Adelaide, Port Lincoln, Willunga and Encounter Bay. Learn more about Australia Post's history here: http://auspo.st/1C0gYkJ
Once mail trucks started to become more common, though, certain modifications had to be made to accommodate vehicles for delivery in snowy weather. Here is a mail truck adapted to use extra wheels and special treads that was used in snowy Nevada County, California, in 1940, as photographed by Russell Lee.