Rhaetia 0-4-4-2 Locomotives in Switzerland

Class Details by Steve Llanso of Sweat House Media

Class G 2/2 + 2/3 (Locobase 12747)

Data from [], last accessed 21 June 2011. Works numbers were 958-989.

Seeking more power and more fuel and water stowage, the RhB ordered a pair of articulateds from SLM that essentially repeated the dimensions of the earlier 0-4-4-0Ts shown in Locobase 12745. The specification called for the design to handle 77 short tons at 15 km/h (9.1 mph) up a 4 1/2% grade. Each locomotive had a name: Maloja and Chiavenna, respectively.

A big difference was the provision of a traling truck on an Adams axle under the footplate. Wikipedia explains that the design was externally framed. It had no pivot point for the rear set of drivers, but rather a set of pivot bearings that allowed the bogie to articulate on curves. Buffer springs and radially displacing crosshead guides with springs centered the lead bogie.

Each set of valve gear was controlled by two overhead camshafts coupled and balanced with an inside rod.

The hoped-for improvement in ride quality didn't happen. Flanges still wore and still carved the rails as well. Later articulateds would carry their pony trucks under the smokebox.

All RhaetiaBahn steam was retired soon after the RB was electrified in 1919. In the case of the 23 and 24, the industrial railway Kraftwerk Oberhasli bought them in 1926 and operated them until 1940.

Principal Dimensions by Steve Llanso of Sweat House Media

ClassG 2/2 + 2/3
Locobase ID12747
Number in Class2
Road Numbers23-24
Number Built2
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)10.50 / 1.60
Engine Wheelbase (ft / m)23 / 7.01
Ratio of driving wheelbase to overall engine wheelbase 0.46
Overall Wheelbase (engine & tender) (ft / m)23 / 7.01
Axle Loading (Maximum Weight per Axle) (lbs / kg)22,322 / 10,125
Weight on Drivers (lbs / kg)88,626 / 40,200
Engine Weight (lbs / kg)98,106 / 44,500
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)98,106 / 44,500
Tender Water Capacity (gals / ML)898 / 3.40
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 1.30 / 1
Minimum weight of rail (calculated) (lb/yd / kg/m)37 / 18.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)41.30 / 1050
Boiler Pressure (psi / kPa)203.10 / 14
High Pressure Cylinders (dia x stroke) (in / mm)12.99" x 21.65" / 330x550
Low Pressure Cylinders (dia x stroke) (in / mm)19.29" x 21.65" / 490x550
Tractive Effort (lbs / kg)21,012 / 9530.89
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.22
Heating Ability
Tubes (number - dia) (in / mm)
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)
Firebox Area (sq ft / m2)75.32 / 7
Grate Area (sq ft / m2)13.99 / 1.30
Evaporative Heating Surface (sq ft / m2)850 / 79
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)850 / 79
Evaporative Heating Surface/Cylinder Volume255.96
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation2841
Same as above plus superheater percentage2841
Same as above but substitute firebox area for grate area15,297
Power L12342
Power MT233.03

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