4-8-0 Steam Locomotives in Argentina

Class Clase 11C (Locobase 2854)

Data from "4-8-0 Type Locomotive for the Buenos Ayres [sic] Great Southern", Railway Engineer, Volume 45, No 8 (August 1924), pp. 291-292. Carlos Alberto Fernandez Priotti in Bryan Attewell ([] Steam Locomotive simulator program (December 2000) and D Rock Carling, 4-8-0 Tender Locomotives (New York: Drake Publishers Inc, 1972), p. 71-72, serial #194 in table pp. 106-107; D[ouglas] S[tuart] Purdom, British Steam on the Pampas (London: Mechanical Engineering Publications, Ltd, 1977), pp. 53-54 delivered 20 in 1924, 30 more in 1928 (4245-4274).

Tall, Belpaire-boilered, oil-fired freight engine first supplied by Armstrong-Whitworth (25 in 1924) that were "among the heaviest and most powerful goods engines ever put on the rail in Argentina." (Nock, RWC V, pl 121).

Purdom noted that their low axle loading of 16 long tons (17.9 short tons) "ensur[ed] good route availability." They pulled 1,500-2,000 ton fruit trains from the Rio Negro Valley in trains, according to Purdom, whose "increased loads imposed on the existing form of drawbars and couplings ...caused rather a lot of breakages." Moreover, its power encouraged high running speeds that turned relatively small drivers at such high rpm that "wear and tear on the axleboxes was heavy.

As with any three-cylinder design, he adds, "maintenance was a little heavy, though no trouble was experienced with the crank axles." Part of the problem was an Argentinian opinion that "any inside motion was considered awkward and inaccessible by the staff." Its attention, he remarked, " could at times be improved."

Even so, Purdom contends", [i]n terms of cargo handled and revenue earned this class must have paid for itself hands down within a comparatively short period." An example of its versatility was its assignment to a heavy sleeper train (up to 20 sleeping cars and a "luggage van" (North American "baggage car") that left Buenos Aires at 10:30 PM, arriving at Mar del Plata after running on a "very easy schedule".

The third cylinder carried on the centerline under the smokebox allowed the class to develop more power at a lower boiler pressure. Two likely advantages -- smoother action in the motion and lower boiler maintenance cost--seem to offset any additional maintenance difficulty caused by the center cylinder's location. Weir pumps and feed water heaters were fitted in the first 40 locomotives, but later removed.

Fuel oil capacity in the tender is shown in long tons.

Beyer-Peacock's 1929 batch differed enough in detail (especially the 21% decrease in superheater area) as to appear in Locobase 20634.

All of the 11Cs went through the privately held ASTARSA shops beginning in 1957, Purdom added, "and an excellent job has been made of the lot." Self-adjusting Franklin wedges for the coupled axle boxes, letting the engines "run like sewing machines when in good trim." Their exhausts were improved as well and sand boxes now rode on top of the boiler.

Carling offered a full list of the update, beginning with the comment that it was based on Andre Chapelon's design, said Carling. It produced a long list of modification at moderate cost ("about a seventh of that of a general overhaul"). Jacking up the boiler pressure to the limits of the design was only one change. Small tube alterations meant fewer gases through the flues. Fuel combustion was now completed in the firebox, thanks to an improved oil burner. Valve chests received new liners and valves and pistons had new rings and the steam circuit benefited from better exhaust passage design and a single Kylchap exhaust. Valve gear used a new combination lever.

Greater power required frame strengthening, "especially the cross bracing". Driving axle horns now used automatically adjusted wedges and mechanical lubricators served bearing, valves, and pistons, Carling added.

For the same fuel consumption, power increased between 26% to 40%. When using the same power as before, consumption dropped 16% to 40%. Average fuel consumption when hauling 1,500-2,000 tons came out as 30% lower.

"So much had the performance improved, " Carling concluded, "that they took over duties from larger and more recently built 4-8-0s, such as haulage of fast perishable traffic, despite their smaller wheels."

In 1967, the class still numbered 75 and remained the "backbone of the heavies good and grain traffic on the Southern Railway", also sharing in express operation.

Class Clase 11C - 1929 (Locobase 20634)

Data from D[ennis] Rock Carling, 4-8-0 Tender Locomotives (New York: Drake Publishers Inc, 1972), p. 71-72 and serial #195 in table pp. 106-107; and D[ouglas] S[tuart] Purdom, British Steam on the Pampas (London: Mechanical Engineering Publications, Ltd, 1977), pp. 53-54.

After Armstrong-Whitworth delivered 55 of this tall, three-cylinder, Belpaire-boilered, oil-fired freight engine design in 1924 and 1927 (Locobase 2854), Beyer, Peacock produced an additional 20 to similar specs.

As noted in the earlier entry, the third cylinder carried on the centerline under the smokebox allowed the class to develop more power at a lower boiler pressure. Two likely advantages -- smoother action in the motion and lower boiler maintenance cost--seem to offset any additional maintenance difficulty caused by the center cylinder's location.

But in the 1929 engines, the firebox heating surface area decreased slightly, but the superheater area fell by 21%. Locobase supposes that the original design was replaced by another variation of the basic Schmidt firetube superheater or the boiler surrendered one-fifth of its flues and superheater elements.

At the same time, adhesion weight rose by 5,600 lb (2,540 kg), lowering the fraction of Loaded tender weight climbed an impressive 31,472 lb (14,275 kg) thanks to increases of 37.5% in water capacity and 31.4% in oil fuel.

Class Clase 15A "Estrella" (Locobase 4309)

Data provided by Carlos Alberto Fernandez Priotti in Bryan Attewell ([] Steam Locomotive simulator program (December 2000); and "Oil-Fired Passenger Engine and Tender for the Buenos Ayres [sic] Great Southern Railway", Vulcan Foundry Locomotive Catalogue, No. 67, found on Flicker's Historical Locomotive Images website at []. See also D[ennis] Rock Carling, 4-8-0 Tender Locomotives (New York: Drake Publishers Inc, 1972), p. 72 and serial #196 in table XI, pp. 106-107; and D[ouglas] S[tuart] Purdom, British Steam on the Pampas (London: Mechanical Engineering Publications, Ltd, 1977), pp. 74-75. (Many thanks to Jorge Cerezo Toledo for his 26 June 2021 email containing links to several sites including the Vulcan Catalogue referred to above.) Works numbers were 4822-4829 in 1938.

Fernandez says these Belpaire-boilered engines were "inspired" by the earlier twelve-wheelers. If so, they were simplified by removing one of the cylinders and increasing piston valve diameters to 10" (254 mm). They also had more cylinder volume and taller drivers. In fact, a comparison with other BAGS designs shows that these were derived directly from the 12K Pacifics (or vice versa) that were delivered in the same years.

Carling notes that the taller drivers on this octet reflected their role as haulers of fasts freight and perishable goods trains. Purdom wrote that the 15A easily handled the heavy night trains to Mar del Plata as well as the fruit trains rushing down from the Rio Negro valley. They were, he said in sum, "capable mixed-traffic engines in every sense of the term."

[Locobase notes the several classes of Twelve-wheelers that rolled on drivers taller than those under the most modern Consolidations. England's Great Western Railway 4700 class 2-8-0s (Locobase 2348) also rolled on 68" drivers on similar service, but these nine proved the exception.)

The Spanish-language website members.es.tripod.de/rielsud/locoayer.html (December 2001) said that when JWH Rae became Chief Mechanic of the Sud in 1935, he split the order for eight engines in this class between four with Walschaert's gear (1550-1553) and four (1554-1557) with Caprotti valve gear. The Caprotti engines were later converted to Walschaerts. D S Purdom wrote that "Extensive tests were carried out to determine the merits or otherwise of the Caprotti valve gear and the thermic syphons, but the results were inconclusive." He added that "in general terms all engines of the series performed in the same excellent manner."

When World War II's world-wide impact complicated supplying Caprotti gear spares to Argentina, the BAGS's Escalada workshops cast new piston valves and produced four sets of Walschaert's gear as well.

All had names and, in order of road number, they were: Estrella, Lucero, Cometa, Centella, Tronador, Orion, Aconcagua, Meteoro.

Vulcan built 30 more of this design with detail differences; see Locobase 2457.

Class Class 15B (Locobase 2457)

Some data from Carlos Alberto Fernandez Priotti in Bryan Attewell ([] Steam Locomotive simulator program (April 2000), supplemented by "Thirty '15B' Class 4-8-0 for the Buenos Ayres [sic] Great Southern Railway", Vulcan Magazine, archived at [], last accessed 7 July 2007. See also D[ennis] Rock Carling, 4-8-0 Tender Locomotives (New York: Drake Publishers Inc, 1972), p. 72 and serial #197 in table XI, pp. 106-107; and Andres Bilstein, Breves del Vapor (V): las clase 15B del Roca, posted 20 Junio 2024 on the Historias del Riel website at [], last accessed 22 December 2024. Works numbers were 5628-5657

A repeat order of 4-8-0s similar, but lighter, than the Class 15A that had been delivered to the Buenos Aires Great Southern before World War II (Locobase 4309). The Spanish-language website members.es.tripod.de/rielsud/locoayer.html (December 2001) said the 15Bs had completely redesigned steam passages (although they retained the characteristic Belpaire boilers).

The first six had names: General Peron, Eva Peron, Coronel J F Castro, 24 de Febrero, 1 de Marzo, 4 de Junio.

Andres Blistein's commentary (in Spanish, paraphrased jointly by Google and Locobase) described the class's work. They supported "various services on the main road, highlighting for several years in the Rio Negro valley pulling train loads of more than 1,000 tons operating on passenger train schedules and running on single track. With the possible exception of one or two faster Rioca trains, 15B proved to be more than capable of hauling every type of train throughout the network with notable fuel economy and maintenance."

1958-1959's reworking of these engines used Andre Chapelon's design, said Carling. It produced a long list of modifications at moderate cost ("about a seventh of that of a general overhaul"). Jacking up the boiler pressure to the limits of the design was only one change. Small tube alterations meant fewer gases through the flues. Fuel combustion was now completed in the firebox, thanks to an improved oil burner. Valve chests received new liners and valves and pistons had new rings and the steam circuit benefited from better exhaust passage design and a single Kylchap exhaust. Valve gear used a new combination lever.

Greater power required frame strengthening, "especially the cross bracing". Driving axle horns now used automatically adjusted wedges and mechanical lubricators served bearing, valves, and pistons, Carling added.

For the same fuel consumption, power increased between 26% to 40%. When using the same power as before, consumption dropped 16% to 40%. Average fuel consumption when hauling 1,500-2,000 tons came out as 30% lower.

"So much had the performance improved, " Carling concluded, "that they took over duties from larger and more recently built 4-8-0s, such as haulage of fast perishable traffic, despite their smaller wheels."