Alexander William (Sonny) Frazer turned 21 in 1919, and he is recorded on the Electoral Roll as working in Wyandra as a carrier.

The photos below are from an album belonging to his wife, Bernadine Monica Frazer (nee Grant). The images capture the Frazers making the transition from using only bullock teams and horses, to moving stock and goods by tractor and truck. (The tractor appears to be a 1920's Fordson Model F).

…”uniquely Australian, was the development of the giant flat-top wagon. These carried loads which in most places would have justified the building of a railway. The point was, though, that Australian sheep stations produced only one, extremely valuable, crop a year, not enough to justify a railway. This wool had to be transported to the nearest navigable water or railway station as quickly as possible, not because it spoilt (wool lasted for years in storage or transit) but so the grazier could sell it at the spring sales and so maintain his cash flow.

The response was the development of the giant flat-top wagon, worked by teams of up to thirty horses or bullocks. These required space to operate, since the leading animals were more than 100 feet (30m) from the swivel-pin, the all-important piece of ironmongery through which traction was transmitted to the wagon. It was more than twenty feet (6m) long with front wheels five feet (1.6m) and back wheels seven feet (2.2m) in diameter. These carried loads of up to an extraordinary 32 tons, or as much as a modern articulated truck. Wool and wheat were the main commodities they carried, although their enormous size meant they were also well suited to lighter goods such as chaff and hay, the all-important fuel for their equine motive power. From 1880s to the 1930s, these giant wagons delivered the riches of Australia's interior to the wharves along the Murray, Darling and Murrumbidgee rivers, and to railway stations from Hay to Cloncurry. The extremely spacious layouts of these New South Wales and Queensland inland railway stations (which survive to the present) were designed with these wagons in mind.” 

Linking a Nation: Australia's Transport and Communications 1788 - 1970 - Chapter 3: By Track and Road: Animal Power and Australian Transport, 1788-1920            http://www.environment.gov.au/heritage/ahc/publications/linking-a-nation/chapter3