West Midland No. 106 to 111
Great Western Railway No. 196 to 201
In 1862, the West Midland Railway ordered six express locomotives with a 2-4-0 wheel arrangement from Beyer, Peacock & Co. for their topographically more demanding routes. They featured straight outer frames and a polished brass steam dome. At the same time, six locomotives with the wheel arrangement 2-2-2 were built, which had the same boiler. As early as 1863, the WMR was merged into the GWR, with the locomotives being given the numbers 196 to 201.
In the years 1879 to 1881 three of the locomotives were converted into tank locomotives, giving them a slightly longer wheelbase, a new boiler and larger cylinders. Number 198 was also rebuilt in 1884 with the same boiler and cylinders, but remained a tender locomotive.
Since the conversion of the 198 obviously proved to be the best, the three locomotives that had already been converted into tank locomotives and the remaining two were also converted in the same way between 1885 and 1887. The six sister machines with the 2-2-2 wheel arrangement had already been converted to the same form in 1882, with no part remaining the same apart from the front frame section. A final rebuild of all machines took place between 1893 and 1905, using a new boiler with a raised firebox top.
Technical data
General
| Property | as built | rebuilt 1879 | rebuilt 1893 |
|---|---|---|---|
| Built | 1862 | 1879-1881 | 1893-1905 |
| Manufacturers | Beyer, Peacock & Co. | ||
| Wheel arrangement | 2-4-0 (Porter) | 2-4-0T (Porter) | 2-4-0 (Porter) |
| Gauge | 1,435 mm (Standard gauge) | ||
Dimensions and weights
| Property | as built | rebuilt 1879 | rebuilt 1893 |
|---|---|---|---|
| Wheelbase | 4.37 m | 5.18 m | 5.03 m |
| Service mass | 29.1 t | 34.3 t | |
| Adhesion mass | 19.2 t | 22.7 t | |
| Rigid wheelbase | 4.37 m | 5.18 m | 5.03 m |
| Axle load | 9.6 t | 12.5 t | |
| Water capacity | 4,546 l | ||
| Empty mass | 31.3 t |
Boiler
| Property | as built | rebuilt 1879 | rebuilt 1893 |
|---|---|---|---|
| Firebox surface | 8.361 m² | 9.197 m² | 9.476 m² |
| Tube heating surface | 87.793 m² | 111.298 m² | 109.533 m² |
| Evaporative heating surface | 96.155 m² | 120.495 m² | 119.009 m² |
| Total heating surface | 96.2 m² | 120.5 m² | 119.0 m² |
Power plant
| Property | as built | rebuilt 1879 | rebuilt 1893 |
|---|---|---|---|
| Driver diameter | 1,829 mm | 1,880 mm | |
| Expansion type | simple expansion | ||
| Cylinders | two, 406 x 508 mm | two, 432 x 610 mm | |
| Boiler pressure | 9.7 bar | ||
Power
| Property | as built | rebuilt 1879 | rebuilt 1893 |
|---|---|---|---|
| Power source | steam | ||
| Estimated power | 298 kW (405 PS) | 373 kW (507 PS) | 447 kW (608 PS) |
| Starting effort | 49.6 kN | ||
Calculated values
| Property | as built | rebuilt 1879 | rebuilt 1893 |
|---|---|---|---|
| Power-to-weight ratio | 10.3 kW/t | 13.0 kW/t | |
| Heating Surface Equivalent | 138.0 m² | 166.5 m² | 166.4 m² |
| Cylinder volume/HSE | 1 : 955.30 | 1 : 1,072.43 | 1 : 1,073.01 |
| Adhesive weight/Total | 1 : 1.51 | 1 : 1.52 | |
| Firebox/Tube surface | 1 : 10.50 | 1 : 12.10 | 1 : 11.56 |
| Factor of adhesion | 1 : 4.48 | ||
| Optimal speed | 55 km/h | ||
| Tractive force/Heating surface | 1 : 8.71 |