The first batch of 17 B18¼ class locomotive were built by the North Ipswich Railway Workshops in 1926.

Per Queensland Railway's classification system they were designated the B18 class, B representing they had three driving axles, and the 18 the cylinder diameter in inches.

[1][2][3] Further orders saw the class total 83 by 1947 with some built by Walkers Limited.

The early examples were painted prussian blue with the boilers having a natural finish.

[1][2][3] Media related to Queensland B18¼ class locomotives at Wikimedia Commons