The 1800 class railmotors were a class of self-propelled diesel railmotors built by Commonwealth Engineering, Granville for the Queensland Railways.

In 1949, the Queensland Railways placed an order for 12 aluminium two-carriage 1800 class railmotors with Commonwealth Engineering, Granville.

The railmotors seated 55 passengers and were delivered to Queensland Railways between 1952 and 1954.

However, the 1800 class were not popular with passengers as they featured uncomfortable seating, poor riding qualities and inadequate ventilation for Queensland's humid subtropical climate.

[2] Two trailer carriages, one of which is converted from a railmotor, remain in service on the Gulflander, operating between Normanton and Croydon, and one complete railmotor is preserved at the Rosewood Railway Museum.