The two South Australian Railways F Class (1st) locomotives were built in England in 1869 by the Avonside Engine Company of Bristol. No. 21 entered service on the South Australian Railways in September 1869; No. 22 followed in October.

South Australian Railways F class (1st)
SAR "first F class" locomotive no. 21 at Nairne station in the Adelaide Hills, about 1884
Type and origin Power type Steam Builder Avonside Engine Company Serial number 773 & 774 Build date 1869 Total produced 2 Rebuilder South Australian Railways Rebuild date 1880 Number rebuilt 2
Specifications Configuration: ​  • Whyte 4-4-0T  • UIC 2'B T Gauge 5 ft 3 in (1,600 mm) Driver dia. 4 ft 11+1⁄2 in (1,511 mm) Loco weight 30 long tons 16 cwt (69,000 lb or 31.3 t) Boiler pressure 130 psi (896 kPa) Cylinders 2 Cylinder size 14 in × 22 in (356 mm × 559 mm) Valve gear Stephenson valve gear
Performance figures Tractive effort 9,500 lbf (42 kN)
Career Operators South Australian Railways Class F Number in class 2 Numbers 21 & 22 First run 1869 Withdrawn 1892 Disposition Both scrapped

The locomotives' initial role was to take over hauling goods trains from the A class locomotives on the new Roseworthy to Tarlee line. They then operated on the Port Adelaide and in the Adelaide hills, where they pulled passenger and goods trains. Near the end of their short working life they shunted in the Adelaide Yards. In 1892, the engines were being rebuilt when a workshop crane lifted them without using hornplates, dropping and seriously damaging them in the process; they were declared to be beyond repair and scrapped afterwards.[1][2][3]

Ten years later, a second group of locomotives, a suburban tank with a 4-6-2 wheel arrangement, took on the "F" class classification.

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