LMS Hughes Crab
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| Type and origin | |
|---|---|
| Power type | Steam |
| Designer | George Hughes |
| Builder |
|
| Build date | 1926–1932 |
| Total produced | 245 |
| Specifications | |
|---|---|
| Configuration: |
|
| • Whyte | 2-6-0 |
| • UIC | 1′C h2 |
| Gauge | 4 ft 8 1⁄2 in (1,435 mm) standard gauge |
| Leading dia. | 3 ft 6 1⁄2 in (1.080 m) |
| Driver dia. | 5 ft 6 in (1.676 m) |
| Length | 59 ft 3 7⁄8 in (18.082 m) |
| Loco weight | 66 long tons (67 t; 74 short tons) |
| Fuel type | Coal |
| Fuel capacity | 5 long tons (5.1 t; 5.6 short tons) |
| Water cap | 3,500 imp gal (16,000 L; 4,200 US gal) |
| Firebox: • Firegrate area |
27.5 sq ft (2.55 m2) |
| Boiler | LMS type G9HS |
| Boiler pressure | 180 lbf/in2 (1.24 MPa) |
| Heating surface: • Tubes |
1,361 sq ft (126.4 m2), later 1,345 sq ft (125.0 m2) |
| • Firebox | 160 sq ft (15 m2) |
| Superheater: |
|
| • Heating area | 307 sq ft (28.5 m2) |
| Cylinders | Two, outside |
| Cylinder size | 21 in × 26 in (533 mm × 660 mm) |
| Performance figures | |
|---|---|
| Tractive effort | 26,580 lbf (118.23 kN) |
| Career | |
|---|---|
| Operators | |
| Power class | LMS: 4 later 5P4F, later 5P5F, later 6P5F, later 5 |
| Numbers | LMS 13000–13244, renumbered 2700–2944 in 1934, BR 42700–42944 |
| Nicknames | Crab |
| Withdrawn | 1961–1967 |
| Disposition | Three preserved, remainder scrapped |
The London Midland and Scottish Railway (LMS) Hughes Crab or Horwich Mogul is a class of mixed traffic 2-6-0 steam locomotive built between 1926 and 1932. They are noted for their appearance with large highly-angled cylinders to accommodate a restricted loading gauge.
These locomotives were referred to as "Crabs". Several authors have claimed that this refers to the resemblance to a crab's pincers of the outside cylinders and valve motion. Another suggestion is that the nickname refers to the "" motion felt on the footplate when the engine is being worked hard, due largely to the inclined cylinders, producing a sensation that it is walking along the track. In some areas they also received the nickname "frothblowers" from their tendency to prime easily when the boiler was overfilled, or the feedwater contaminated.
Designed by George Hughes, Chief Mechanical Engineer of the LMS, and built at the ex-L&YR works at Horwich and the ex-LNWR works at Crewe, they were put into service by his successor, Henry Fowler. The design incorporated a number of advanced features for the time such as long travel valves, compensated brake gear, a new design of tender and a new boiler, the latter based on the one fitted to Hughes' four-cylinder Baltic tank locomotives built at Horwich.
Fowler tried to have the design altered to use standard Derby components. However the design process and pre-production were sufficiently advanced to prevent the fitting of a smaller Derby pattern boiler, and the cylinders and motion also remained as designed by Hughes. The tender was replaced by a Derby standard type, which was narrower than the cab. Standard Midland Railway boiler fittings and brake equipment were also substituted, and the class became something of a hybrid design. Nevertheless they performed rather well in most circumstances and gained a strong reputation in some areas, especially in Scotland, where they became the preferred locomotive for heavy unfitted mineral work on difficult routes, even after the introduction of the Stanier mixed traffic 4-6-0s.
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Wikipedia