2-8-0 Steam Locomotives in Argentina

Class Clase 11A (Locobase 6370)

Data from Vulcan Foundry catalogue, ca. 1920 and D[ouglas] S[tuart] Purdom, British Steam on the Pampas (London: Mechanical Engineering Publications, Ltd, 1977), pp. 53-54

As part of the Sud's interest in two-stage steam use, Vulcan supplied these cross-compound goods Consolidation locomotives. Instead of the more usually adopted Von Borries-design automatic intercepting valve installed in the smokebox, wrote Purdom, the builder mounted the intercepting valve on top of the HP cylinder. "Operated by the reversing lever, [the valve] enabled greater effort to be applied when starting a train from rest."

All of the class kept their compound set up to the extent that when the class reached the point of needing heavy repairs, the shops fitted the class with new high-pressure cylinders using piston valves, a new firebox, and both tube plates. Half of the class of 28 left in 1948 underwent conversion to simple expansion.

Class Clase 11B-simple (Locobase 4302)

Data from Carlos Alberto Fernandez Priotti in Bryan Attewell ([] Steam Locomotive simulator program (December 2000).

Virtually identical to the Class 8 Prairie tank series imported by this railroad in the same years. Like many British-built locomotives in Argentina, these were fitted with Belpaire boilers.

Apparently this Consolidation was just the right size (or price, or both) for the traffic, because Beyer Peacock, North British, and Vulcan in Britain and Henschel in Germany added to the stud over the next 18 years.

The Spanish-language website members.es.tripod.de/rielsud/locoayer.html (Dec 2001) notes that the first 60 supplemented in 1931 by an additional order for 40 to handle the rapid increase in traffic over the Sud's mainline. It's a little surprising to note that these low-drivered Consolidations established a monopoly on the passenger trains between Buenos Aires-La Plata and Bahia Blanca-Toay. Sometime later the entire class was converted to oil-burning.

Class Clase 11D (Locobase 4303)

Data provided by Carlos Alberto Fernandez Priotti in Bryan Attewell ([] Steam Locomotive simulator program (Decemberl 2000); and FC General Roca 6-1957 Locomotive Diagrams supplied in August 2021 by Allen Stanley from his extensive Rail Data Exchange collection. See also D[ouglas] S[tuart] Purdom, British Steam on the Pampas (London: Mechanical Engineering Publications, Ltd, 1977), pp. 46-47

Class 11 was a goods-engine catchall it appears, as this three-cylinder Consolidation class shares the main designation with a 2-8-0 design from fourteen years earlier and a twelve-wheeler delivered in the same years. In fact, this 2-8-0 seems a scaled-down version of the Mastodon, with a smaller, lower-pressure boiler driving the same piston volume and driver diameter.

Purdom described the 11D's service "nothing very remarkable", homing in on the "Tandil area where heavy stone and livestock orginates,and they had a reputation for doing excellent work on low fuel consumption."