Queensland Railways class B15
The class B15 was a 4-6-0 introduced by the Queensland Railways in 1889. The B in the designation stood for three driving axles, while the 15 was the cylinder diameter in inches. It was a mixed traffic locomotive like the B13, but more powerful. After the first 15 had been built by Nasmyth, Wilson & Co., more followed from three other manufacturers. In total 92 were built for the QR and six similar locomotives were acquired from the Chillagoe Railway & Mining Co. in 1919. Due to damages on the rails, one was fitted with drivers of 45 instead of 36 inches in 1900. Over the following three decades, most class members were also rebuilt in this way. They were used in the Cairns area during most of their careers and numbers 290 and 299 were later preserved.
Technical data
General
| Property | as built | enlarged drivers |
|---|---|---|
| Built | 1889-1899 | 1900-1930 |
| Manufacturers | Nasmyth, Wilson & Co., Evans, Anderson, Phelan & Co., Yorkshire Engine Co., Walkers | North Ipswich |
| Wheel arrangement | 4-6-0 (Ten-wheeler) | |
| Gauge | 1,067 mm (Cape gauge) | |
Dimensions and weights
| Property | as built | enlarged drivers |
|---|---|---|
| Total wheelbase | 13.89 m | |
| Service mass | 28.4 t | 32.1 t |
| Adhesion mass | 21.3 t | 24.3 t |
| Total mass | 52.6 t | 57.9 t |
| Rigid wheelbase | 2.67 m | |
| Axle load | 8.1 t | |
| Water capacity | 7,730 l | |
| Fuel capacity | 6.1 t (coal) | |
Boiler
| Property | as built | enlarged drivers |
|---|---|---|
| Grate area | 1.208 m² | 1.189 m² |
| Firebox surface | 7.432 m² | 8.083 m² |
| Tube heating surface | 68.748 m² | 66.983 m² |
| Evaporative heating surface | 76.181 m² | 75.066 m² |
| Total heating surface | 76.2 m² | 75.1 m² |
Power plant
| Property | as built | enlarged drivers |
|---|---|---|
| Driver diameter | 914 mm | 1,143 mm |
| Boiler pressure | 11 bar | |
| Expansion type | simple expansion | |
| Cylinders | two, 381 x 508 mm | |
Power
| Property | as built | enlarged drivers |
|---|---|---|
| Power source | steam | |
| Estimated power | 224 kW (305 PS) | |
| Starting effort | 75.6 kN | 60.5 kN |
Calculated values
| Property | as built | enlarged drivers |
|---|---|---|
| Factor of adhesion | 1 : 2.77 | 1 : 3.94 |
| Optimal speed | 18 km/h | 23 km/h |
| Power-to-weight ratio | 7.9 kW/t | 7.0 kW/t |
| Heating Surface Equivalent | 113.3 m² | 115.5 m² |
| Cylinder volume/HSE | 1 : 1,022.00 | 1 : 1,003.05 |
| Adhesive weight/Total | 1 : 1.33 | 1 : 1.32 |
| Tractive force/Heating surface | 1 : 20.73 | 1 : 16.83 |
| Grate area/Heating surface | 1 : 63.06 | 1 : 63.13 |
| Firebox/Tube surface | 1 : 9.25 | 1 : 8.29 |