Rx 93

National Railway Museum, Port Adelaide

This scanned slide view is courtesy of John Hurst and shows Rx 93 at the former Mile End Railway Museum in Adelaide.

The juxtaposition with the big 4-8-4 No.504 situated behind was likely intentional, providing a visual representation of the changes brought to the SAR

under the Webb era, with the 500 class and other ‘big engines’ replacing double-headed Rx locos on top link expresses over the Adelaide Hills.

Builder	Dubs & Co, Glasgow
Builder’s Number & Year	2142 of 1886
Wheel Arrangement	4-6-0
No. in class	84

This locomotive was built by Dubs & Co, Glasgow, Scotland as the third of the original six members of the R-class 4-6-0 locomotives for the South Australian Railways (SAR), designed by the notable locomotive engineer William Thow. The adoption of a 4-6-0 wheel arrangement stemmed from the need for more powerful locomotives to tackle the grades of the Mount Lofty Range and would have been a significant innovation in 1886; indeed the R-class came 8 years before the famous Highland Railway ‘Jones Goods’ class of 1894 which introduced the 4-6-0 wheel arrangement to the British Isles.

R 93 was rebuilt to Rx specification in 1910 by via adoption of a larger Belpaire boiler, albeit still using saturated steam. A few of the Rx class also received superheaters. The Rx-class ultimately grew to 84 examples comprising the 30 original R-class locos rebuilt to Rx specification, together with a further 54 built new, becoming the South Australian Railway's most numerous type of broad-gauge steam locomotive.

The Rx-class were assigned to both passenger and freight turns until the arrival of larger locomotives in the 1920's during the Webb era, which was characterised by a modernisation of the SAR locomotive fleet with large locos along American design principles, although supplied by UK manufacturers. Many Rx locos were withdrawn in the mid-1930, but the remainder settled in to branch line, suburban and shunting roles. In this capacity some lasted to the end of regular SAR steam operations.

Rx 93 was the last of the original six Dubs-built R-class locos when condemned by the SAR on 28 October 1966. Interestingly this writing-off the books occurred one month after Rx 93 entered the collection of the newly formed Mile End Railway Museum! Today this historic locomotive is the oldest of the preserved Rx class and the only surviving Rx to have originally been built as R-class. Rx 93 carries a fine copper-top chimney rather than the basic stovepipe chimney carried by several of its preserved sisters, and is paired with a larger bogie tender - but would have been paired with a smaller 6-wheel tender when first supplied by Dubs & Co. Today it is a prime exhibit at the fine National Railway Museum at Port Adelaide.

Rx 93 is a prime exhibit within the National Railway Museum, Port Adelaide, as seen is this digital photo of 24 September 2005.

It wears a beautiful lined black livery and retains an ornate copper-capped chimney.

References

a	Fluck R. E., Sampson R., & Bird K. J. 'Steam locomotives and Railcars of the South Australian Railways', published by The Mile End Railway Museum (SA) Inc, 1986.
b	Wikipedia entry for SAR R & Rx Class locos: South Australian Railways R class - Wikipedia retrieved 11 August 2025.

Page updated: 24 October 2025

Government Railways:	NSWGR	QGR	CR	WAGR	VR	TGR	SAR	Contributions	Home
Private & Industrial Railways:	NSW	QLD	Sugar	WA	Vic	Tas	SA	Copyright