[1] After the South Australian Railways had its new B class tank engines built to run on the railway line to Gawler, two more locomotives were purchased to also run this service on the lightly engineered line.

Their range was increased to include stops at Roseworthy and Kapunda following the opening of the new line extension in August 1860.

In 1884 and 1885, both locomotives were rebuilt and put back into traffic, having acquired new cabs which were complete with circular front and side windows.

The C class worked on the northern lines until they were superseded by more powerful locomotives.

6 continued to work on the suburban system and performed shunting duties at Mile End and Port Adelaide, eventually being withdrawn and scrapped in 1926 after 70 years of service.