Prior to completion of the through standard gauge railway to Melbourne in 1962, a railway journey from Sydney required a change between the standard gauge NSWGR and the broad gauge Victorian Railways at the border station of Albury.  To operate the broad gauge portion of the "Spirit Of Progress" express, the Victorian Railways built four very handsome "S-class" 3-cylinder pacific locomotives at Newport Workshops between 1928 & 1930.

In 1937 the four S-class pacifics received art-deco streamlining and larger 6-wheel bogie tenders to enable non-stop running between Melbourne and Albury. In addition, modern rolling stock was built and painted a handsome royal blue with twin yellow stripes; the S-class locomotives received matching livery, the resulting streamlined trainsets making a striking image and featuring prominently in Victorian Railways publicity of the day.

In their final years of operation the S-class locomotives were converted from coal to oil firing.  They were replaced by first-generation diesel locomotives on the Spirit of Progress from 1952 and quickly withdrawn from service.  Finding no other use, all four S-class locomotives had been scrapped by 1954 however the large tender tanks were retained for stationary purposes and the tender underframes converted to 6-wheel bogie "QH" wagons.  At least two of the tender tanks have survived into the preservation era, together with all four of the QH wagons.

The grounded tender tank of S 301 is held by the Seymour Railway Heritage Centre and had been displayed on one of the turntable roads at the former Seymour locomotive depot.  In more recent years it has been reunited with S-class tender underframe "QH1" however further restoration work is awaited.

A second surviving tender body is held by ARHS Victoria Division and was stored at Ballarat East Depot until transported to Newport in late 2004.  The remaining S-class tender underframes (as QH wagons) are also scattered around Newport Workshops.

Here is a Wikipedia link providing further history and photographs for the S-class pacifics.