Rio Grande do Sul 4-8-4 Locomotives in Brazil


Class Details by Steve Llanso of Sweat House Media

Class 1001 (Locobase 268)

Data from 1946 Locomotive Cyclopedia. (Thanks to Teemu Koivumaki for his 8 February 2023 that supplied the Alco builder's card S-1979 - October 1945 that at long last filled in many blanks.) Works numbers were 72930-72947 in October 1945, 73767-73778 in 1946. See Locobase 20324 for the later batch from Montreal Locomotive Works.

These engines ran on the Rio Grande do Sul's metre gauge. Their physical proportions deceive the eye until you notice the size of the cab. One of the smallest 4-8-4s built for any railroad, one suspects, and ones equipped with relatively tall drivers for the metre gauge. For comparison, see Locobase 1127 for Chapelon's design for the same gauge. Regardless of its dimensions, the design featured several firebox additions such as arch tubes (14 sq ft/1.30 sq m)) and thermic syphons (59 sq ft/5.48 sq m) and an enormous twelve-wheel tender.

See Locobase 20999 for an extended summary of a May 1953 trip on the BNR's duplicate 4-8-4 which describes the challenges of operating steam locomotives on poor coal, the high quality of the crews, and the likely benefits of electricification.

After service in Brazil, many of these Northerns went on to serve on the Bolivian State Railway from the mid-1950s to 1980.

NB: see Locobase 13987 for an overview of the RG do Sul as described by Lionel Wiener in 1912.


Class 1001-MLW (Locobase 20324)

Data from 1946 Locomotive Cyclopedia. Works numbers were 74873-74887) in 1946

A second batch of metre-gauge 4-8-4s (the first 27 appear in Locobase 268). One of the smallest 4-8-4s built for any railroad, they were equipped with relatively tall drivers. For comparison, see Locobase 1127 for Chapelon's design for the same gauge.

NB: see Locobase 13987 for an overview of the RG do Sul as described by Lionel Wiener in 1912.

Principal Dimensions by Steve Llanso of Sweat House Media

Class10011001-MLW
Locobase ID268 20324
RailroadRio Grande do SulRio Grande do Sul
CountryBrazilBrazil
Whyte4-8-44-8-4
Number in Class2715
Road Numbers1001-10271028-1042
GaugeMetreMetre
Number Built2715
BuilderAlco-SchenectadyMontreal LW
Year19451946
Valve GearBakerBaker
Locomotive Length and Weight
Driver Wheelbase (ft / m)15.75 / 4.8015.75 / 4.80
Engine Wheelbase (ft / m)37.01 / 11.2837 / 11.28
Ratio of driving wheelbase to overall engine wheelbase 0.43 0.43
Overall Wheelbase (engine & tender) (ft / m)72.93 / 22.23
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)115,000 / 52,163115,200 / 52,254
Engine Weight (lbs / kg)216,000 / 97,976217,000 / 98,430
Tender Loaded Weight (lbs / kg)170,100 / 77,156
Total Engine and Tender Weight (lbs / kg)386,100 / 175,132
Tender Water Capacity (gals / ML)5280 / 20
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)22 / 20
Minimum weight of rail (calculated) (lb/yd / kg/m)48 / 2448 / 24
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)59 / 149959 / 1499
Boiler Pressure (psi / kPa)235 / 16.20246.60 / 17
High Pressure Cylinders (dia x stroke) (in / mm)17.99" x 27.99" / 457x71118" x 28" / 457x711
Tractive Effort (lbs / kg)30,669 / 13911.2432,230 / 14619.30
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.75 3.57
Heating Ability
Tubes (number - dia) (in / mm)112 - 2" / 51
Flues (number - dia) (in / mm)32 - 5.375" / 137
Flue/Tube length (ft / m)16.99 / 5.18
Firebox Area (sq ft / m2)301 / 27.96301 / 27.97
Grate Area (sq ft / m2)56.51 / 5.2556.50 / 5.25
Evaporative Heating Surface (sq ft / m2)2054 / 190.822054 / 190.89
Superheating Surface (sq ft / m2)652 / 60.57652 / 60.59
Combined Heating Surface (sq ft / m2)2706 / 251.392706 / 251.48
Evaporative Heating Surface/Cylinder Volume249.44249.07
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation13,28013,933
Same as above plus superheater percentage16,46717,277
Same as above but substitute firebox area for grate area87,71192,041
Power L126,45527,720
Power MT2028.632121.95

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