London, Chatham & Dover classes M, M1 and M2
Great Britain 1877 18 produced
For the heaviest of the boat trains between London and Dover, William Kirtley designed the class M, of which six were built by Neilson & Co. in 1877. Two further orders had to be placed in part with the company's own workshops in Longhedge. Four class M1 locomotives and eight class M2 locomotives followed, which were almost identical to the first. All locomotives received new boilers between 1898 and 1904. They were retired between 1911 and 1923.
Technical data
General
| Property | M | M1 | M2 |
|---|---|---|---|
| Built | 1877 | 1880-1881 | 1884-1885 |
| Manufacturers | Neilson & Co. | Longhedge | Dübs & Co., Longhedge |
| Wheel arrangement | 4-4-0 (American) | ||
| Gauge | 1,435 mm (Standard gauge) | ||
Dimensions and weights
| Property | M | M1 | M2 |
|---|---|---|---|
| Wheelbase | 6.41 m | ||
| Service mass | 44.5 t | ||
| Adhesion mass | 28.4 t | ||
| Total mass | 77 t | 75.2 t | 73.7 t |
| Rigid wheelbase | 2.54 m | ||
| Axle load | 14.2 t | ||
| Water capacity | 11,591 l | ||
| Fuel capacity | 4.1 t (coal) | ||
Boiler
| Property | M | M1 | M2 |
|---|---|---|---|
| Grate area | 1.514 m² | ||
| Firebox surface | 9.941 m² | ||
| Tube heating surface | 89.373 m² | ||
| Evaporative heating surface | 99.313 m² | ||
| Total heating surface | 99.3 m² | ||
Power plant
| Property | M | M1 | M2 |
|---|---|---|---|
| Driver diameter | 1,981 mm | ||
| Boiler pressure | 9.7 bar | ||
| Expansion type | simple expansion | ||
| Cylinders | two, 444 x 660 mm | ||
Power
| Property | M | M1 | M2 |
|---|---|---|---|
| Power source | steam | ||
| Estimated power | 298 kW (405 PS) | ||
| Starting effort | 54.0 kN | ||
Calculated values
| Property | M | M1 | M2 |
|---|---|---|---|
| Factor of adhesion | 1 : 5.16 | ||
| Optimal speed | 34 km/h | ||
| Power-to-weight ratio | 6.7 kW/t | 4.0 kW/t | |
| Heating Surface Equivalent | 149.0 m² | ||
| Cylinder volume/HSE | 1 : 1,375.40 | ||
| Adhesive weight/Total | 1 : 1.56 | ||
| Tractive force/Heating surface | 1 : 11.36 | ||
| Grate area/Heating surface | 1 : 65.60 | ||
| Firebox/Tube surface | 1 : 8.99 | ||
