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

Class Details by Steve Llanso of Sweat House Media

Class 8E (Locobase 3747)

Data from "Three-Cylinder Locomotives for Suburban Service, Buenos Ayres Great Southern Ry", Locomotive Magazine, Volume XXIX [29], No 376 (15 December 1923), pp. 349-350. Earlier information from Carlos Alberto Fernandez Priotti in Bryan Attewell ([] Steam Locomotive simulator program (April 2000). See also OS Nock (Railways of the World in Colour - Volume V, - Railways at the Zenith of Steam 1920-40 (New York: Macmillan Company, 1970 - in Great Britain Blandford Press), plate 166 and p. 177); and D S Purdom, British Team on the Pampas (London and New York: Mechanical Engineering Publications, Ltd:, 1977), pp. 17

Fernandez said these were part of a 62 locomotive order from several British builders delivered from 1922-1930 to cope with the heavy suburban traffic out of Buenos Aires. Hawthorn Leslie delivered the first 12 (3530-3541) in 1922-24. North British supplied the next 15 (3542-3556) in 1924-25. Vulcan produced the balance in two batches -- 3557-3581 in 1925-27 and 3582-3591 in 1930.

Using the Adriatic wheel arrangement more often found in Europe, these Belpaire-boilered locomotives served Buenos Aires suburban commuter traffic. Purdom wrote that by 1923, the ten-car trains included 82-ft (25 m) cars offering 100 seats in a first-class carriage and 150 seats in a second-class one. Train loads grew to over 400 tons tare (i.e., without passenger). He adds "With close spacing between stations the locomotive working had to be smart and the repeated accelerations called for an all-out effort" during a 22-hour period in which each locomotive had three crews.

LM's 1923 report noted that the class's tractive effort was calculated at 26,346 lb (11,950 kg; 117.19 kN) when using a coefficient of 0.75 of mean effective pressure. All three pistons measured 10" (254 mm) in diameter. They were laid out with the two outside valves on top of their cylinders and the middle one under its cylinder. LM repeated frequent assertions about the three-cylinder setup: It distributed working stresses, allowed large bearing surfaces and "a crank axle of simple and robust design." Moreover, three uniformly space cranks offered a superior turning moment. Given those qualities, LM wondered why more three-cylinder suburban engines weren't procured.

The Spanish-language website members.es.tripod.de/rielsud/locoayer.html (Dec 2001) comments that although they required careful maintenance, this class was extremely reliable throughout their lives. Purdom wrote these "masters of the enormous suburban traffic around Buenos Aires" registered decades of "hard slogging" that piled up 10,000 km (6,210 miles) per month and delivered "exceptionally low fuel consumption." He added that reducing costs was a major reason for removing the originally installed Weir feed pumps and feed water heater as well as mechanical lubricators.

Nock wrote that the BAGS wanted to encourage good maintenance in 1949, so they repainted four of them in liveries similar to four pre-Grouping British railways. "one in Caledonian blue, one in Midland Red, one in North British olive, and one in North Easter green." Liking the olive green best, the railway repainted others, to little avail and "...there was soon a reversion to black, with yellow lines, as previously."

Retirements began in 1959 with the "coup de grace" coming in 1962. Even then, 21 were held in reserve and in an "indian summer" of activity, were brought back into service to handle a traction crisis (motive power crunch) in 1966-67. RielSud comments that they handled their assigned tasks with efficiency.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID3747
RailroadFC del Sud de Buenos Aires (FCS)
Number in Class62
Road Numbers3530-3591
Number Built62
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)16.50 / 5.03
Engine Wheelbase (ft / m)37.17 / 11.33
Ratio of driving wheelbase to overall engine wheelbase 0.44
Overall Wheelbase (engine & tender) (ft / m)37.17 / 11.33
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)127,232 / 57,712
Engine Weight (lbs / kg)218,288 / 99,014
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)218,288 / 99,014
Tender Water Capacity (gals / ML)2400 / 9.09
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)1205 / 4560.90
Minimum weight of rail (calculated) (lb/yd / kg/m)71 / 35.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)68 / 1727
Boiler Pressure (psi / kPa)200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)17.5" x 26" / 445x660 (3)
Tractive Effort (lbs / kg)29,859 / 13543.83
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.26
Heating Ability
Tubes (number - dia) (in / mm)136 - 1.875" / 48
Flues (number - dia) (in / mm)21 - 5.375" / 137
Flue/Tube length (ft / m)12.50 / 3.81
Firebox Area (sq ft / m2)136 / 12.63
Grate Area (sq ft / m2)25 / 2.32
Evaporative Heating Surface (sq ft / m2)1340 / 124.49
Superheating Surface (sq ft / m2)292 / 27.13
Combined Heating Surface (sq ft / m2)1632 / 151.62
Evaporative Heating Surface/Cylinder Volume123.42
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation5000
Same as above plus superheater percentage5900
Same as above but substitute firebox area for grate area32,096
Power L19704
Power MT504.44

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