South Australian Railways '710' class 2-8-2

Designed by SAR Chief Mechanical Engineer Fred Shea
Built at Islington Railway Workshops 1928-1929

CYLINDERS (2) 22 ins x 28 ins (559mm x 711mm)
COUPLED WHEEL DIAMETER 57 ins (1,447.8mm)
TOTAL HEATING SURFACE 3,245 square feet (301.5m2)
(including superheater)
GRATE AREA 47 square feet (4.4m2)
BOILER PRESSURE 200 PSI (1,379kpa)
TRACTIVE EFFORT 40,400 lbs (18,325.4kg)
TOTAL WEIGHT 175.75 tons (178.6 tonnes)
LENGTH OVERALL 75 feet 7¾ ins (23,056.9mm)

The 710 class locomotive was the home-grown development of Webb's 700 class 'Mikado type' delivered from Armstrong Whitworth three years earlier. As the third of Webb's big engines proved to be such a success, it was decided to build another ten of them at Islington. Modifications included the fitting of a front-end throttle, cross compound air compressor, thermic syphons and a much larger capacity tender.

To increase hauling capacity boosters were also incorporated but this turned out to be their Achilles heel, the heavier axle loading on the trailing 'Delta' truck prevented the locomotive working over the lighter track work. A feed water heater was also trialed on one of the locomotives for a short period.

The boosters were eventually removed and as with the 700's the 710's became a useful and versatile locomotive hauling freight all over the broad gauge network as well as working country and suburban passenger trains. Only one of the big 'Mikados' remain today, Number 702 can be found at the National Railway Museum Port Adelaide.