50 Years of Q & A: Our own elevating scraper?
We’re looking for a machine that first displayed the principles of an elevating scraper, some of you would probably pick the 1950s and the Hancock scraper as the start of the 'breed'. We see the principle of the elevating scraper as being a single machine that excavates material in one location, transports it to a second location and discharges it, with the3 excavation and transport elements of the machine being separate. Click here to see pics of what we’ve managed to dig up ...
The horse-drawn scraper believed to have excavated for rail lines in the 1890s
The picture shows a horse-drawn cart with hopper doors at the bottom. There is a cart wheel on one side and a segmented steel wheel on the other side. A plough share diverted earth into the segments off the wheel as the cart travelled forward, and the rotation of the wheel saw the soil elevated until it spilt from the wheel onto a chute that channelled it into the cart.
When the cart was full, the cart was then taken to the fill area where a lever was tripped to open the clamshell doors at the bottom of the dump body. When the load had been discharged, the operator turned a hand wheel to return the doors to their original position, where they tripped a latch that held them in place.
This excavator, or one similar to it, worked on the Trans Australia Railway Line. It was abandoned 40 miles west of Port Augusta and may still be there, covered by sand
The scraper was found on a farm north of Moree, and local legend had it that the machine was used in construction of the Great Northern line. Given the location where it was found, it may well have been used on the Mungindi Railway Line, which reached Moree in 1897 (ref. Wikipedia).
This line reached Mungindi in 1914, but given that a much larger and more sophisticated self-propelled excavator using similar principles was working on the Trans Australia Railway line by this time, it is likely that the horse drawn scraper predates it by a considerable period of time, making the 1890s or early 1900s the most likely time of construction: it could be even earlier.
Given the similarity to self-propelled machines known to have been built by Wesley Castles, it is the horse-drawn scraper that should probably be attributed to him as well, given the uniqueness of the design.
The machine on the Trans Australia Railway line was powered by the largest engine ever built by A. H. McDonald (of static roller fame). There were two hollow wheels at the rear, with each discharging onto a conveyor. The conveyor on one side discharged into the conveyor on the other side, so that all spoil was cast to one side.
It is likely that multiple self-propelled machines existed: correspondence has been sighted where Wesley Castles claims to have multiple machines with Thornycroft engines working. An unusual aspect of this correspondence is that Wesley Castles withdrew his offer to sell a machine to a government department and instead altered the offer to hire on a cubic yard rate. This offer, in the early 1910s, seems ahead of its time.
Sources: “A.H. McDonald Industrial Pioneer” Kenneth Neal McDonald, published 1998 / “The Desert Railway” Patsy Adam Smith, published 1974
Next week's question:
Has there ever been an Australian excavator with a boom at each end?
And if so, who built it?