Weyerhaeuser Timber 2-6-6-2ST
The Weyerhaeuser Timber Co. was one of the American logging railroads which used Mallets instead of geared steam locomotives for their steep and winding lines. They hoped that these would be easier to maintain than a Shay, while having the same flexibility. Their first 2-6-6-2ST saddle tank locomotive No. 110 was delivered by Baldwin in 1928 for lines with grades between four and eight percent. It was oil fired for reduced fire risk when running in dry forests. The water tank was split into two parts which were located on sides of the boiler. In accordance with the original Mallet principle, it was a compound.
In the next year numbers 105 and 106 followed, but in contrast to the first one these had four cylinders of the same size. In other respects they were identical to 110, but heavier. In 1929, Baldwin delivered No. 111 that also worked with simple expansion, but had a much larger boiler. Some years later in 1936, Baldwin delivered three more which included the second No. 110, No. 112 and No. 9. These were again nearly identical to the first No. 110, but had larger cylinders.
111 was retired as the first one in 1947. It was sold to Canadian Forest Products and used on Vancouver Island until 1962. The others were used by Weyerhaeuser until the fifties and several were then sold to Rayonier, where they received an additional tender. The first 110 was restored between 1999 and 2001 and is today running on the Black Hill Central. The second 110 was sold to the California Western in 1967 to haul the Super Skunk tourist train. Later it came to the San Diego Railroad Museum.
Technical data
General
| Property | 110/1 | 105, 106 | 111 | 110/2, 112, 9 |
|---|---|---|---|---|
| Built | 1928 | 1929 | 1936 | |
| Manufacturers | Baldwin | |||
| Wheel arrangement | 2-6-6-2ST (Mallet Mogul) | |||
| Gauge | 1,435 mm (Standard gauge) | |||
Dimensions and weights
| Property | 110/1 | 105, 106 | 111 | 110/2, 112, 9 |
|---|---|---|---|---|
| Wheelbase | 11.51 m | |||
| Service mass | 100.7 t | 111.6 t | 119.7 t | 112 t |
| Adhesion mass | 83 t | 94.3 t | 99.8 t | 95.3 t |
| Rigid wheelbase | 2.44 m | |||
| Fuel capacity | 4,542 l (oil) | |||
| Water capacity | 12,113 l | 9,464 l | ||
Boiler
| Property | 110/1 | 105, 106 | 111 | 110/2, 112, 9 |
|---|---|---|---|---|
| Grate area | 2.434 m² | 3.855 m² | 2.434 m² | |
| Firebox surface | 11.892 m² | 13.192 m² | 11.892 m² | |
| Tube heating surface | 141.77 m² | 200.485 m² | 141.77 m² | |
| Evaporative heating surface | 153.662 m² | 213.677 m² | 153.662 m² | |
| Superheater surface | 33.259 m² | 54.163 m² | 33.259 m² | |
| Total heating surface | 186.9 m² | 267.8 m² | 186.9 m² | |
Power plant
| Property | 110/1 | 105, 106 | 111 | 110/2, 112, 9 |
|---|---|---|---|---|
| Driver diameter | 1,118 mm | |||
| Boiler pressure | 13.8 bar | 14.5 bar | 13.8 bar | |
| Expansion type | compound | simple expansion | compound | |
| Cylinders | four, HP: 432 x 610 mm and LP: 660 x 610 mm | four, 406 x 610 mm | four, HP: 457 x 610 mm and LP: 711 x 610 mm | |
Power
| Property | 110/1 | 105, 106 | 111 | 110/2, 112, 9 |
|---|---|---|---|---|
| Power source | steam | |||
| Estimated power | 820 kW (1,115 PS) | 1,119 kW (1,521 PS) | 820 kW (1,115 PS) | |
| Starting effort | 167.0 kN | 211.2 kN | 221.7 kN | 189.1 kN |
| Starting effort simple | 200.4 kN | 227.0 kN | ||
Calculated values
| Property | 110/1 | 105, 106 | 111 | 110/2, 112, 9 |
|---|---|---|---|---|
| Factor of adhesion | 1 : 4.88 | 1 : 4.38 | 1 : 4.41 | 1 : 4.94 |
| Optimal speed | 31 km/h | 24 km/h | 31 km/h | 26 km/h |
| Power-to-weight ratio | 8.1 kW/t | 7.3 kW/t | 9.3 kW/t | 7.3 kW/t |
| Heating Surface Equivalent | 279.6 m² | 388.0 m² | 279.6 m² | |
| Cylinder volume/HSE | 1 : 1,385.16 | 1 : 1,131.11 | 1 : 815.29 | 1 : 1,581.78 |
| Adhesive weight/Total | 1 : 1.21 | 1 : 1.18 | 1 : 1.20 | 1 : 1.18 |
| Tractive force/Heating surface | 1 : 18.66 | 1 : 23.60 | 1 : 17.29 | 1 : 21.13 |
| Grate area/Heating surface | 1 : 76.80 | 1 : 69.48 | 1 : 76.80 | |
| Firebox/Tube surface | 1 : 11.92 | 1 : 15.20 | 1 : 11.92 | |
| Total/Superheater | 1 : 4.62 | 1 : 3.95 | 1 : 4.62 | |