Southern Pacific class M-6
originally class EF
United States 1901 102 produced
The Southern Pacific class M-6, originally designated class EF, were Vauclain compound Moguls with drivers of 63 inches introduced in 1901. In the first year, Baldwin built 68 and 23 more were built between 1902 and 1903. Four more identical locomotives went to the Texas & New Orleans. Between 1907 and 1914, all were rebuilt with two simple cylinders and soon also superheated. In 1917 and 1918, the SP built three more in their own shops at Sacramento which were simple and superheated from the start. The class was retired between 1934 and 1958.
Technical data
General
| Property | as built | superheated |
|---|---|---|
| Built | 1901-1903, 1917-1918 | |
| Manufacturers | Baldwin, Sacramento | |
| Wheel arrangement | 2-6-0 (Mogul) | |
| Gauge | 1,435 mm (Standard gauge) | |
Dimensions and weights
| Property | as built | superheated |
|---|---|---|
| Wheelbase | 7.21 m | 7.26 m |
| Service mass | 75.4 t | 83.8 t |
| Adhesion mass | 65.4 t | 72.1 t |
| Rigid wheelbase | 4.62 m | |
| Axle load | 21.8 t | 24 t |
| Water capacity | 22,712 l | |
Boiler
| Property | as built | superheated |
|---|---|---|
| Grate area | 4.599 m² | |
| Firebox surface | 14.894 m² | 15.794 m² |
| Tube heating surface | 194.788 m² | 170.663 m² |
| Evaporative heating surface | 209.682 m² | 186.457 m² |
| Total heating surface | 209.7 m² | 221.1 m² |
| Superheater surface | 34.653 m² | |
Power plant
| Property | as built | superheated |
|---|---|---|
| Driver diameter | 1,600 mm | |
| Boiler pressure | 13.8 bar | |
| Expansion type | compound | simple expansion |
| Cylinders | four, HP: 394 x 711 mm and LP: 660 x 711 mm | two, 533 x 711 mm |
Power
| Property | as built | superheated |
|---|---|---|
| Power source | steam | |
| Estimated power | 969 kW (1,317 PS) | 1,156 kW (1,572 PS) |
| Starting effort | 119.1 kN | 148.2 kN |
| Starting effort simple | 143.0 kN | |
Calculated values
| Property | as built | superheated |
|---|---|---|
| Factor of adhesion | 1 : 5.38 | 1 : 4.77 |
| Optimal speed | 50 km/h | 48 km/h |
| Power-to-weight ratio | 12.8 kW/t | 13.8 kW/t |
| Heating Surface Equivalent | 284.2 m² | 334.7 m² |
| Cylinder volume/HSE | 1 : 1,466.71 | 1 : 949.55 |
| Adhesive weight/Total | 1 : 1.15 | 1 : 1.16 |
| Tractive force/Heating surface | 1 : 11.87 | 1 : 14.00 |
| Grate area/Heating surface | 1 : 45.59 | 1 : 48.08 |
| Firebox/Tube surface | 1 : 13.08 | 1 : 10.81 |
| Total/Superheater | 1 : 5.38 |
