Midland class 2000
London, Midland & Scottish class 3P
The Midland Railway's class 2000 was a heavy suburban tank locomotive designed in the tradition of the popular 0-4-4T wheel arrangement, but with an additional driving axle. The water tanks extended to the smokebox and, in conjunction with the shape of the side windows in the cab, led to the nickname “flatiron”. Another feature was the cutouts in the water tanks, which guaranteed accessibility to the inside motion.
The boiler was replaced between 1920 and 1926 with a new one with superheater and Belpaire firebox. In order to guarantee sufficient curve negotiation, the first driving axle was designed with lateral play. This was probably the cause for the oscillations at higher speeds, which led to several derailments. They were soon only used in freight service and were withdrawn between 1935 and 1938.
Technical data
General
| Property | as built | superheated |
|---|---|---|
| Built | 1907 | 1920-1926 |
| Manufacturers | Derby | |
| Wheel arrangement | 0-6-4T | |
| Gauge | 1,435 mm (Standard gauge) | |
Dimensions and weights
| Property | as built | superheated |
|---|---|---|
| Length | 12.31 m | |
| Wheelbase | 8.53 m | |
| Service mass | 73.6 t | 77.8 t |
| Adhesion mass | 53.5 t | 56.4 t |
| Rigid wheelbase | 2.59 m | |
| Water capacity | 10,183 l | |
| Fuel capacity | 3.6 t (coal) | |
Boiler
| Property | as built | superheated |
|---|---|---|
| Grate area | 1.951 m² | |
| Firebox surface | 11.613 m² | 11.474 m² |
| Tube heating surface | 112.088 m² | 96.944 m² |
| Evaporative heating surface | 123.701 m² | 108.418 m² |
| Total heating surface | 123.7 m² | 131.9 m² |
| Superheater surface | 23.504 m² | |
Power plant
| Property | as built | superheated |
|---|---|---|
| Driver diameter | 1,702 mm | |
| Boiler pressure | 12.1 bar | |
| Expansion type | simple expansion | |
| Cylinders | two, 470 x 660 mm | |
Power
| Property | as built | superheated |
|---|---|---|
| Power source | steam | |
| Estimated power | 559 kW (760 PS) | 708 kW (963 PS) |
| Starting effort | 87.9 kN | |
Calculated values
| Property | as built | superheated |
|---|---|---|
| Factor of adhesion | 1 : 5.97 | 1 : 6.30 |
| Optimal speed | 39 km/h | 50 km/h |
| Power-to-weight ratio | 7.6 kW/t | 9.1 kW/t |
| Heating Surface Equivalent | 181.8 m² | 212.8 m² |
| Cylinder volume/HSE | 1 : 1,260.16 | 1 : 1,076.40 |
| Adhesive weight/Total | 1 : 1.37 | 1 : 1.38 |
| Tractive force/Heating surface | 1 : 14.84 | 1 : 13.91 |
| Grate area/Heating surface | 1 : 63.40 | 1 : 67.62 |
| Firebox/Tube surface | 1 : 9.65 | 1 : 8.45 |
| Total/Superheater | 1 : 4.61 |
