London & South Western class 700 “Black Motor”
Great Britain 1897 30 produced
In 1897 Drummond had 30 freight locomotives built, which he had designed while still with the Caledonian. Construction eventually took place at Dübs in Scotland and they were nicknamed “Black Motors”. From 1919 all locomotives were fitted with a superheater, with the smoke box being extended. This process was continued under the Southern Railway and lasted until 1929. The superheater was partly of the Eastleigh works design and partly of the Maunsell design. Most locomotives were retired in 1961 and 1962.
Technical data
General
| Property | as built | superheated |
|---|---|---|
| Built | 1897 | 1919-1929 |
| Manufacturers | Dübs & Co. | Eastleigh |
| Wheel arrangement | 0-6-0 (Six-coupled) | |
| Gauge | 1,435 mm (Standard gauge) | |
Dimensions and weights
| Property | as built | superheated |
|---|---|---|
| Length | 8.42 m | 8.88 m |
| Length loco | 16.03 m | 16.49 m |
| Wheelbase | 5.03 m | |
| Total wheelbase | 11.91 m | |
| Empty mass | 39.2 t | 43.2 t |
| Service mass | 43.4 t | 47.4 t |
| Adhesion mass | 43.4 t | 47.4 t |
| Total mass | 80.7 t | 84.7 t |
| Rigid wheelbase | 5.03 m | |
| Axle load | 16.6 t | 17.3 t |
| Water capacity | 15,910 l | |
Boiler
| Property | as built | superheated |
|---|---|---|
| Grate area | 1.892 m² | |
| Firebox surface | 11.52 m² | 10.87 m² |
| Tube heating surface | 99.128 m² | 79.85 m² |
| Evaporative heating surface | 110.648 m² | 90.72 m² |
| Total heating surface | 110.6 m² | 106.2 m² |
| Superheater surface | 15.515 m² | |
Power plant
| Property | as built | superheated |
|---|---|---|
| Driver diameter | 1,549 mm | |
| Boiler pressure | 12.1 bar | 12.4 bar |
| Expansion type | simple expansion | |
| Cylinders | two, 470 x 660 mm | two, 483 x 660 mm |
Power
| Property | as built | superheated |
|---|---|---|
| Power source | steam | |
| Estimated power | 522 kW (710 PS) | 671 kW (912 PS) |
| Starting effort | 96.5 kN | 104.7 kN |
Calculated values
| Property | as built | superheated |
|---|---|---|
| Factor of adhesion | 1 : 4.41 | 1 : 4.44 |
| Optimal speed | 34 km/h | 39 km/h |
| Power-to-weight ratio | 12.0 kW/t | 14.1 kW/t |
| Heating Surface Equivalent | 168.2 m² | 176.1 m² |
| Cylinder volume/HSE | 1 : 1,361.41 | 1 : 1,371.96 |
| Adhesive weight/Total | 1 : 1.00 | |
| Tractive force/Heating surface | 1 : 18.22 | 1 : 20.59 |
| Grate area/Heating surface | 1 : 58.48 | 1 : 56.15 |
| Firebox/Tube surface | 1 : 8.60 | 1 : 7.35 |
| Total/Superheater | 1 : 5.85 | |
