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Southern Pacific classes MM-2 and AM-2
One of the first classes of cab forward locomotives of the Southern Pacific were Mallets with a total of six coupled axles and one leading and one trailing axle each. Their designation was thus MM-2 for “Mallet Mogul”...
| Southern Pacific classes MM-2 and AM-2Remove | |
|---|---|
| Variant | MM-2 |
| Built | 1911 |
| Manufacturers | Baldwin |
| Wheel arrangement | (1C)C1 ma |
| Gauge | 1435 mm |
| Length | |
| Service mass | 174543 kg |
| Top speed | |
| Power | |
| Engine |
General
| Property | Southern Pacific classes MM-2 and AM-2MM-2 |
|---|---|
| Built | 1911 |
| Manufacturers | Baldwin |
| Wheel arrangement | 2-6-6-2 (Mallet Mogul) |
| Gauge | 1,435 mm |
Dimensions and weights
| Property | Southern Pacific classes MM-2 and AM-2MM-2 |
|---|---|
| Wheelbase | 15.65 m |
| Total wheelbase | 25.93 m |
| Service mass | 174.5 t |
| Adhesion mass | 145.6 t |
| Total mass | 258 t |
| Rigid wheelbase | 3.35 m |
| Axle load | 24.3 t |
| Water capacity | 37,854 l |
| Fuel capacity | 12,113 l (oil) |
Boiler
| Property | Southern Pacific classes MM-2 and AM-2MM-2 |
|---|---|
| Grate area | 6.503 m² |
| Firebox surface | 21.832 m² |
| Tube heating surface | 469.811 m² |
| Evaporative heating surface | 491.643 m² |
| Total heating surface | 491.6 m² |
Power plant
| Property | Southern Pacific classes MM-2 and AM-2MM-2 |
|---|---|
| Driver diameter | 1,600 mm |
| Boiler pressure | 13.8 bar |
| Expansion type | compound |
| Cylinders | four, HP: 635 x 711 mm and LP: 965 x 711 mm |
Power
| Property | Southern Pacific classes MM-2 and AM-2MM-2 |
|---|---|
| Power source | steam |
| Estimated power | 1,790 kW (2,434 PS) |
| Starting effort | 293.2 kN |
| Starting effort simple | 351.8 kN |
Calculated values
| Property | Southern Pacific classes MM-2 and AM-2MM-2 |
|---|---|
| Factor of adhesion | 1 : 4.87 |
| Optimal speed | 37 km/h |
| Power-to-weight ratio | 10.3 kW/t |
| Heating Surface Equivalent | 600.8 m² |
| Cylinder volume/HSE | 1 : 1,615.90 |
| Adhesive weight/Total | 1 : 1.20 |
| Tractive force/Heating surface | 1 : 12.46 |
| Grate area/Heating surface | 1 : 75.60 |
| Firebox/Tube surface | 1 : 21.52 |
