The 81s were built by Clyde under license from GM in the early 1980s to help replace the older GMs and Alcos which served the State Rail Authority since the start of dieselisation. They have seen service with SRA,Freightrail/Freightcorp, National Rail and now Pacific National. These locomotives are used on a number of different services including Passenger, Grain, Yard work, Container traffic and occasionally Coal duties. The 81s used in Queensland are mainly for shunting at Acacia Ridge, the occasional trip train to Rocklea and also more recently the Bromelton Stone trains.