Queensland Government Rlys 4-6-4 Locomotives in Australia

Class DD17 (Locobase 9425)

Data from the qrig (queensland railways interest group) site ([], last accessed 5 May 2008).

Cape-gauge tanks for Brisbane Northside passenger service, these "Blue Babies" had a relatively long career given how late into the steam era they first appeared. They were in fact later expressions of the D17 tanks of the same wheel arrangement that had entered service in 1924.

Mike Quirk of QRIG notes that the class revealed a tendency toward breaking driving axles and coupling rods when they first entered service. Modifications included modifying the horn cheeks (which carry the axle boxes) and using "Vibroc" alloy steel rods. Once those improvements had been made, the design was able to exploit its other late-steam qualities such as self-cleaning fireboxes, roller bearings, and long-travel piston valves.

The Workshops Rail Museum fact sheet on its preserved DD17 (#950) comments: "They were popular locomotives with a reputation for rapid acceleration from stations, ideal for suburban train services." When diesels began supplanting the babies in Northside service, the class shifted to the Southside.

Phaseout began in November 1966 and was completed by the end of 1968.