 The locomotives were among the heaviest of locomotives in Australia with a axle load and this along with their width restricted their sphere of operation to Thirroul on the Illawarra line, Wallerawang on the Main Western line and Junee on the Main South line.Due to the immense size of the firebox they could not be hand fired and had to use a mechanical stoker, thus becoming the first New South Wales locomotive class to use a mechanical stoker.They were later followed by the 58 class and the 60 class 

They were not permitted to operate on the Main Northern line due to load limitations on some bridges and a tighter loading gauge.