FC del Sud de Buenos Aires 4-6-0 Locomotives in Argentina

Class Class 12A simpled (Locobase 4304)

Data provided by Carlos Alberto Fern+ndez Priotti in Bryan Attewell ([] Steam Locomotive simulator program (December 2000).

These 12As were originally compounds (like the 12Bs mentioned elsewhere) supplied by Beyer, Peacock & Co and North British and may have been repeats of the 12Bs. Like most Argentine locomotives built in Britain, these had Belpaire boilers.

The BAGS superheated and simpled them in 1922-1926, making them identical to the 1915 12Ds. At the same time, says the Spanish-language website members.es.tripod.de/rielsud/locoayer.html (December 2001), they were converted to oil-burning.

Class Class 12B (Locobase 2721)

Data from "Balanced Compound Locomotive, Buenos Aires Great Southern Ry," The Locomotive Magazine, Vol XIII [13] (14 September 1907), p. 166-167. Works numbers were 2192-2199 in 1907.

When the BAGS' stock of engines proved too lightly powered for the heavier express trains of the period, the company ordered these four-cylinder balanced compounds based on the Great Northern's compound Atlantics. They had high-pitched Belpaire boilers, piston valves worked by Walschaerts valve gear and a stolid, bluff look enhanced by the dark livery. The LM report describes the operation of the Vulcan patent starting valve and its patent reversing gear in considerable detail.

The 12Bs operated on main-line trains for over 30 years.

Class Class 12B-superheated (Locobase 20019)

Data from the Vulcan Foundry site at [], last accessed 25 September 2015. See also Douglas S Purdom, British Steam on the Pampas (London: Mechanical Engineering Publications, Ltd, 1977), pp. 61-62.

Locobase couldn't say when the eight 12Bs supplied by Vulcan in 1907 (Locobase 2721) were rebuilt with superheaters. But Purdom's book pinned down the date for me. The octet retained their Belpaire fireboxes, but traded 58% of their small tubes for the superheater flues.

Purdom also nicely summarized the tradeoffs involved in operating a compound locomotive, which usually led to their early abandonment. "The class 12B", he remarked, "was one of the many cases that have occurred of a design which was claimed to and probably did improve performance and produce fuel economy having to be discarded because of the adverse effect on maintenance brought about by its complication and multiplicity of parts ..." He emphasized that the conflict was "particularly applicable on a railway system such as that of Argentina, where the widely scattered sheds make close supervision of maintenance work very difficult."

Class Class 12D (Locobase 4305)

Data from "Passenger Locomotives, Buenos Ayres [Aires] Great Southern Ry.", Locomotive Magazine, Volume XXII [22] (15 May 1916), pp. 86-87. See also 1946 Beyer, Peacock catalogue hosted on Martyn Bane's website at [] (accessed 21 May 2006); and "Six-Coupled Locomotives for the Buenos Aires Great Southern Railway Co., Ltd", Locomotive News and Railway Contractor, Volume XI [11], No. 5 (10 March 1922), pp. 156-157. Works numbers were 5743-5752 in 1914, 5753-5762 in 1915.

Carlos Alberto Fernandez Priotti in Bryan Attewell ([] Steam Locomotive simulator program (December 2000) says that the twenty engines of this class were "...the speeders of the Buenos Aires Great Southern Railway and were named [after] Argentinian bird species."

Steam entered the cylinders through piston valves, the boiler was backed by a severely square Belpaire firebox made entirely of copper except for the steel tube sheet.

Class Class 12G (Locobase 4307)

Data provided by Carlos Alberto Fern+ndez Priotti in Bryan Attewell ([] Steam Locomotive simulator program (December 2000).

These were rebuilds of earlier Class 12 Ten-wheelers with parts supplied by Vulcan Foundry, says Fernandez.

Class Class 12H (Locobase 4308)

Data provided by Carlos Alberto Fern+ndez Priotti in Bryan Attewell ([] Steam Locomotive simulator program (December 2000). Supplemented and updated by FC General Roca 6 - 1957 supplied in August 2022 by Allen Stanley from his extensive Rail Data Exchange collection.

Like the 12Gs, these were rebuilds of earlier Class 12 Ten-wheelers with parts supplied by Vulcan Foundry, says Fernandez. Diagram notes show just how much of the update was Vulcan: Bastidor completo con ruedas acopladas, ejes y cajas, cilindros, moviemiento y bielas acopladas". Translation: Shorthand- everything below the boiler, firebox and cab. "complete frame, coupled wheels, axles, and axle boxes, cylinders, motion including valve gear, and connecting rod [between crosshead and main driver].

In this case, the boilers were slightly larger and the tenders held more water.