GWR 4000 Class
.jpg)
4003 Lode Star.
|
|||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||
| Type and origin | |
|---|---|
| Power type | Steam |
| Designer | George Jackson Churchward |
| Builder | GWR Swindon Works |
| Build date | 1906-1923 |
| Total produced | 73 |
| Specifications | |
|---|---|
| Configuration: |
|
| • Whyte | 4-6-0 (prototye built as 4-4-2 but rebuilt to 4-6-0 1909). |
| • UIC | 2'Ch4 |
| Gauge | 4 ft 8 1⁄2 in (1,435 mm) standard gauge |
| Leading dia. | 3 ft 2 in (0.965 m) |
| Driver dia. | 6 ft 8 1⁄2 in (2.045 m) |
| Trailing dia. | 1 ft 1 1⁄2 in (0.343 m) (4-4-2 only) |
| Wheelbase | loco: 27 ft 3 in (8.31 m) |
| Loco weight | 75.8 long tons (77.0 t; 84.9 short tons) |
| Tender weight | 40 long tons (41 t; 45 short tons) |
| Water cap | =3,500 imp gal (16,000 l; 4,200 US gal) - 4,000 imp gal (18,000 l; 4,800 US gal) |
| Firebox: • Firegrate area |
27.1 sq ft (2.52 m2) |
| Boiler | GWR Standard No. 1 (with variations) |
| Boiler pressure | 225 psi (1.55 MPa) |
| Heating surface: • Tubes |
1,686.6 sq ft (156.69 m2) |
| • Firebox | 154.8 sq ft (14.38 m2) |
| Superheater | "Swindon No. 3" |
| Cylinders | 4, (2 outside, 2 inside) |
| Cylinder size |
14 1⁄4 in × 26 in (362 mm × 660 mm) - 15 in × 26 in (381 mm × 660 mm) |
| Valve gear | Walschaerts inside |
| Valve type | Piston valves |
| Performance figures | |
|---|---|
| Tractive effort | 25,090 lbf (111.61 kN) - 27,800 lbf (123.66 kN) |
| Career | |
|---|---|
| Operators | Great Western Railway (until 1947); British Railways (until 1957). |
| Class | 4000 or Star |
| Numbers | 4000–4072 |
| Axle load class | GWR: Red |
| Retired | 1926–1957 |
| Disposition | 15 rebuilt as Castle class, 1 preserved, remainder scrapped. |
The Great Western Railway 4000 or Star were a class of 4-cylinder 4-6-0 Ten Wheeler passenger steam locomotives designed by George Jackson Churchward for the Great Western Railway (GWR) in 1906. The prototype was built as a 4-4-2 Atlantic (but converted to 4-6-0 during 1909). They proved to be a successful design which handled the heaviest long distance express trains and established the design principles for GWR 4-cylinder classes over the next twenty-five years.
After finally converting the last broad gauge lines in 1892, the GWR began a period of modernization as new cut-off lines shortened its routes to west of England, South Wales and Birmingham. During the first decade of the twentieth century, the new Chief Mechanical Engineer, George Jackson Churchward designed or acquired a number of experimental locomotives with different wheel arrangements and boiler designs to help him plan for the future motive power needs of the railway. Following the success of the prototypes of his two-cylinder Saint class 4-6-0 locomotives, introduced in 1902, Churchward became interested in developing a more powerful 4-cylinder type for the longer non-stop express services. He therefore persuaded the GWR to acquire three French 4-cylinder 4-4-2 compound locomotives, 102 La France (1904) and 103 President and 104 Alliance (both 1905) for comparison purposes.
In addition to acquiring the French compound locomotives Churchward built and tested his own prototype 4-cylinder locomotive simple-expansion locomotive, No. 40 North Star in 1906. As with some early members of the Saint class it was built as a 4-4-2 but designed so that it could easily be converted to a 4-6-0. It was completed at the Swindon Works of the GWR (Lot 161) in April 1906. It was numbered 40 and later that year was named 'North Star'. In November 1909 it was converted to 4-6-0. The new design incorporated many ideas from the French locomotives including a domeless taper boiler and Belpaire firebox. The design had divided drive with the outside cylinders connected to the second set of driving wheels whilst the inside cylinders were connected to the front set of driving wheels. The valve gear was an unusual design, called scissors gear, which eschewed the use of eccentrics, but was basically a variation on Walschaerts gear. The prototype locomotive was rebuilt as a member of the Castle Class in November 1929.
...
Wikipedia