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Caledonian class 721 “Dunalastair I to IV”
The increasing weight of the express trains in the 1880s and 1890s also presented the Caledonian Railway with the problem that inefficient double-headings had to be used more and more frequently. John F. McIntosh, who...
| Caledonian class 721 “Dunalastair I to IV”Remove | |
|---|---|
| Variant | Dunalastair III |
| Built | 1899-1900 |
| Manufacturers | St. Rollox |
| Wheel arrangement | 2B |
| Gauge | 1435 mm |
| Length | |
| Service mass | 52530 kg |
| Top speed | |
| Power | |
| Engine |
General
| Property | Caledonian class 721 “Dunalastair I to IV”Dunalastair III |
|---|---|
| Built | 1899-1900 |
| Manufacturers | St. Rollox |
| Wheel arrangement | 4-4-0 (American) |
| Gauge | 1,435 mm |
Dimensions and weights
| Property | Caledonian class 721 “Dunalastair I to IV”Dunalastair III |
|---|---|
| Wheelbase | 7.19 m |
| Service mass | 52.5 t |
| Adhesion mass | 36.3 t |
| Total mass | 98.3 t |
| Rigid wheelbase | 2.90 m |
| Axle load | 18.7 t |
| Water capacity | 18,753 l |
| Fuel capacity | 4.6 t (coal) |
Boiler
| Property | Caledonian class 721 “Dunalastair I to IV”Dunalastair III |
|---|---|
| Grate area | 2.137 m² |
| Firebox surface | 12.821 m² |
| Tube heating surface | 135.824 m² |
| Evaporative heating surface | 148.645 m² |
| Total heating surface | 148.6 m² |
Power plant
| Property | Caledonian class 721 “Dunalastair I to IV”Dunalastair III |
|---|---|
| Driver diameter | 1,981 mm |
| Boiler pressure | 12.4 bar |
| Expansion type | simple expansion |
| Cylinders | two, 483 x 660 mm |
Power
| Property | Caledonian class 721 “Dunalastair I to IV”Dunalastair III |
|---|---|
| Power source | steam |
| Estimated power | 611 kW (831 PS) |
| Starting effort | 81.9 kN |
Calculated values
| Property | Caledonian class 721 “Dunalastair I to IV”Dunalastair III |
|---|---|
| Factor of adhesion | 1 : 4.34 |
| Optimal speed | 45 km/h |
| Power-to-weight ratio | 11.6 kW/t |
| Heating Surface Equivalent | 212.8 m² |
| Cylinder volume/HSE | 1 : 1,135.62 |
| Adhesive weight/Total | 1 : 1.45 |
| Tractive force/Heating surface | 1 : 11.51 |
| Grate area/Heating surface | 1 : 69.56 |
| Firebox/Tube surface | 1 : 10.59 |
