The 1170 class (initially numbered the 1500 class, and before that, the 1270 class) were introduced in 1956 as a Diesel-Electric alternative to the PB15 class steam loco. They became the first diesel-electric branch line locos in Queensland. The locos were built under license by Walkers Ltd. Maryborough as their first diesel-electrics.

The 1170s were nicknamed the ‘Pawpaws’ after a racehorse, which in turn was named after a character in a contemporary cartoon strip.

The 1170s spent most of their time based at Townsville, although earlier on they were used in the Brisbane area and southern regions of the state. Later on they were relegated to shunting duties.

Five members of the class have been preserved, with two in operational order. (see below for more information).