4-4-0 Steam Locomotives in Argentina

Class Clase 6 (Locobase 21232)

Data from R. Gould, "Some Particulars of the Results of the Compound Locomotive on the Buenos Aires Great Southern Railway", Proceedings of the Institute of Mechanical Engineers (September 1901), pp. 817-823 and plates. Works numbers were 2944-2949 in 1888.

Gould compared the performance and economy of a pair of Wordsell-von Borries cross-compound, American-type Eight Wheelers (Locobase 21233) to these six simple-expansion engines whose only significant difference was the single use of high-pressure steam..

Class Clase 6A (Locobase 21233)

Data from R. Gould, "Some Particulars of the Results of the Compound Locomotive on the Buenos Aires Great Southern Railway", Proceedings of the Institute of Mechanical Engineers (September 1901), pp. 817-823 and plates. Works numbers were 2944-2949 in 1888.

Gould compared the performance and economy of six simple-expansion Clase 6 American-type Eight Wheelers (Locobase 21232) these two Wordsell-von Borries cross compounds (Locobase 21232). Gould explained the use of this particular compound layout as "being the simplest arrangement, and interfering the least with the duplication of parts." The only significant difference between them was the cylinder and valve layout.

For Gould, at least, the results of the comparison were "so excellent that, with the exception of shunting and local traffic engines, no simple engines (either goods or passenger) have since been ordered." They had "proved easy to handle [and] exhibited a high economy in the use of coal and water." The system allowed the engineer to run "much fuller into gear without lifting the water and thus haul heavier loads."

To his credit, Gould acknowledged the Sud's contribution to the compound's success:

"The absence of heavy grades on the Buenos Aires Great Southern Railway renders it a favorable field for the compound engines ... the bulk of the line being practically straight and level. The character of the traffic, with long runs and full trains as a rule, causing approximation to the fixed load of the stationary engine [i.e. those in powerplants and many steamships], is also favourable for the compound."

The engines did "jib" a bit at first, he acknowledged. Locobase takes "jib" to mean a kind of stuttering hesitation based on Gould's finding that the automatic valve jumped too quickly into compound when starting. This reduced the engine's maximum available power (achieved by admitting HP steam to the LP cylinder), hence the sluggish jerks.Redesigning the valve, he said, solved the problem.

Over the succeeding years, the compounds had been "no more expensive to maintain than the non-compound, whilst the economy of coal and water is beyond question." In sum, Gould's BAGS disciplined approach and understanding of compounding in locomotives stands up well against that of most other railroads operating compounds over more challenging profiles and variable load levels.

Class Clase 6B (Locobase 21234)

Data from R. Gould, "Some Particulars of the Results of the Compound Locomotive on the Buenos Aires Great Southern Railway", Proceedings of the Institute of Mechanical Engineers (September 1901), pp. 817-823 and plates. Works numbers 3175-3184 and 3185-3199, 3210 in 1890

See Locobase 21233 for a summary of CME R Gould's very positive assessment of the Wordsell-von Borries cross-compound system in American-type Eight-wheelers. He wasted little time to add almost two dozen more such engines from the same builder.

Much of the new design retained features of the two prototypes including the relatively low compounding ratio retained features of the two prototypes. An enlarged firebox and grate increased the direct heating surface area of total evaporative surface area.

Class Clase 6E (Locobase 3746)

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

These were originally delivered to the FC Buenos Aires a Ensenada.

Class unknown (Locobase 20833)

Data from "Rolling Stock on the Great Southern Railway, Buenos Ayres", Engineer, Volume 23 (22 February 1867), p. 166.

At the time Engineer showed illustrations of the engine and its passenger carriages, the Sud extended from Buenos Ayres [sic] 78 miles (126 km) south to Chascomas making nine intermediate stops. Virtually all of the way ran level with just one section of 1 in 90 and easy curves. Rails weighed 90 lb/yard (45 kg/metre) and were laid on the ground with no ballast. Over this profile the RS tanks were tasked to take 21 wagons up 1 in 200 (0.5%) at 25 mph (40 kph).

Fuel was imported and thus coal economy was paramount and these engines were credited with consumption rates averaging 9-10 lb/mile (2.53-2.87 kg/km). Under the boiler, compensation levers equalized the bogie and the lead driving axle.