FC del Sud de Buenos Aires 4-6-2 Locomotives in Argentina

Class Class 12E (Locobase 4306)

Data provided by Carlos Alberto Fern+ndez Priotti in Bryan Attewell ([] Steam Locomotive simulator program (December 2000) and No. 45, "Oil-Fired Passenger Engine and Tender for the Buenos Ayres [sic] Great Southernl Railway", Vulcan Foundry Locomotive Catalogue, No. 45, found on Flicker's Historical Locomotive Images website at [], last accessed 26 June 2021. (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 3897-3916 in 1926.

Tall-drivered Pacifics that shared the boiler design with the 4-8-0s delivered in the same year.

The Spanish-language website members.es.tripod.de/rielsud/locoayer.html (December 2001, inactive as of 2021) commented that in looking over the varied motive power of the Sud, it's difficult to choose "the best". But (in rough translation) mechanics and train crew would agree that the title should fall on the 12Es. From the moment they arrived, says Rielsud, (apparently quoting D S Purdom's verdict) the "Treinta y Nueve Grandes" proved themselves regardless of circumstances to be locomotives of low maintenance, running many kilometers between repairs. Purdom noted that there was "some anxiety" from time to time about the inside crank axle, but few problems actually arose. "Careful peiodic defelction tests" kept an eye out for any axle showing fatigue, but such events were "only necessary after something over a million kilometres [621,000 miles] had been run."

Over the years, beginning in the 1930s, the BAGS shops tinkered with the design to further increase efficiency, Purdom noted. Among the modifications were reducing the outside cylinder diameters to 17 1/2" and fitting all three with long-travel valves. Most received double blast pipes and chimineys (stacks). As the crews found that "as the engines always appeared to be working well within capacity with a light exhaust which affected visibility", the shops fitted smoke deflectors.

Four of the engines--3913-3914, 3921, and 3930--received in 1936 larger fireboxes with sloping throat and back plates that offered a larger grate area of 32.6 sq ft (3.03 sq m). "Results with either type [the original or the modified Class 15 boiler] were uniformly good, " Purdom reported.

The 12Es pulled the night trains, sometimes made up of as many as 20 cars, between BA and Bahia Blanca as well as daily passenger hauls to Mar del Plata, Tandil, and Bahia. All but the lead engine (named Mar del Plata) had names of Argentine Army generals. As of mid-1967, all 21 eninges remained "on the books"--40 years after their introduction.

Class Class 12K (Locobase 2856)

Data from heating surfaces and weights provided by Carlos Alberto Fern+ndez Priotti in Bryan Attewell ([] Steam Locomotive simulator program (December 2000)' ; expanded and supplemented by "12K Class Oil-Fired Passenger Engine and Tender for the Buenos Ayres [sic] Great Southern Railway", Vulcan Foundry Locomotive Catalogue, No. 66, found on Flicker's Historical Locomotive Images website at []. See also See also D S Purdom, British Steam on the Pampas-The Locomotives of the Buenos Aires Great Southern Railway (London and New York: Mechanical Engineering Publications Limited, 1977), pp. 69-70 (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 4810-4821 in 1938.

Tall, Belpaire-boilered Pacific intended for intermediate passenger traffic (rather than the fastest expresses). At first the cylinder exhaust passage design choked the engines at high speed, although the boilers steamed freely. These passages were reworked successfully in 1950 using cylinders based on the 15B class 4-8-0 pattern [Locobase 2457]. The result was , says Nock (RWC V, pl 160), "speed of 70 mph [115 kph] on level track with trailing loads of 400 tons became commonplace." And "maintained with the greatest of ease", wrote Purdom. Smoke deflectors proved less successful an upgrade and were removed. The exhaust steam injector (an alternate means of pre-heating a boiler) "was inclinded to be temperamental in the hands of inexperienced men."