Compare locomotives
Add a locomotive
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”...
General
| Property | Southern Pacific classes MM-2 and AM-2 rebuilt AM-2 |
|---|---|
| Built | 1914 |
| Manufacturers | Baldwin |
| Wheel arrangement | 4-6-6-2 |
| Gauge | 1,435 mm (Standard gauge) |
Dimensions and weights
| Property | Southern Pacific classes MM-2 and AM-2 rebuilt AM-2 |
|---|---|
| Wheelbase | 16.71 m |
| Rigid wheelbase | 3.35 m |
| Total wheelbase | 27.05 m |
| Service weight | 192.4 t |
| Adhesive weight | 161.9 t |
| Axle load | 27 t |
| Total weight | 294.9 t |
| Water capacity | 45,425 l |
| Fuel capacity | 14,385 l (oil) |
Boiler
| Property | Southern Pacific classes MM-2 and AM-2 rebuilt AM-2 |
|---|---|
| Grate area | 6.503 m² |
| Firebox surface | 31.959 m² |
| Tube heating surface | 373.749 m² |
| Evaporative heating surface | 405.708 m² |
| Superheater surface | 94.947 m² |
| Total heating surface | 500.7 m² |
Power plant
| Property | Southern Pacific classes MM-2 and AM-2 rebuilt AM-2 |
|---|---|
| Driver diameter | 1,600 mm |
| Boiler pressure | 14.5 bar |
| Expansion type | simple expansion |
| Cylinders | four, 559 x 711 mm |
Power
| Property | Southern Pacific classes MM-2 and AM-2 rebuilt AM-2 |
|---|---|
| Power source | steam |
| Estimated power | 2,386 kW (3,244 PS) |
| Starting effort | 341.6 kN |
Calculated values
| Property | Southern Pacific classes MM-2 and AM-2 rebuilt AM-2 |
|---|---|
| Factor of adhesion | 1 : 4.65 |
| Optimal speed | 43 km/h |
| Power-to-weight ratio | 12.4 kW/t |
| Heating Surface Equivalent | 755.4 m² |
| Cylinder volume/HSE | 1 : 923.59 |
| Adhesive weight/Total | 1 : 1.19 |
| Tractive force/Heating surface | 1 : 14.25 |
| Grate area/Heating surface | 1 : 76.99 |
| Firebox/Tube surface | 1 : 11.69 |
| Total/Superheater | 1 : 4.27 |
