[1] The first batch of 12 engines was built by Baldwin Locomotive Works, Philadelphia in 1902.

This batch was originally of a 4-6-0 wheel arrangement, and was a lighter version of the Ec class, gaining them the Baby Yanks nickname.

A second batch of 10 engines was built by the WAGR's Midland Railway Workshops in 1915, to the modified 4-6-2 design.

Four of these, Cs270 Black Butt, Cs432 Marri, Cs439 Banksia and Cs440 Jarrah were transferred to the Railway Department Sawmill at Banksiadale in the early 1950s and named.

All were included in the sale of the timber mill to Hawker Siddeley Building Supplies in October 1961.