With a Mogul (2-6-0) wheel arrangement widely used in Australia at the time, 129 were built between 1885 and 1898.

Beyer, Peacock & Co, Manchester built 50, James Martin & Co of Gawler 77, and the SAR's Islington Railway Workshops 2.

Between 1904 and 1924, 48 were fitted with new Belpaire boilers and reclassified as the Yx class.

Seven of these were sold in 1948 to the Tasmanian Government Railways, but only four entered service (as F1–F4).

[2][4] As of 2022[update], there were 10 preserved Y and Yx class locomotives (of which Yx141 was operational), as follows: Media related to South Australian Railways Y class locomotives at Wikimedia Commons