LMS Ivatt Class 4
From Wikipedia, the free encyclopedia
 43106, the only preserved class member, at the Rocket 150 event |
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| Power type | Steam |
|---|---|
| Designer | H.G. Ivatt |
| Builder | Horwich, Doncaster and Darlington Works |
| Build date | 1947-1952 |
| Total production | 162 |
| Configuration | 2-6-0 |
| UIC classification | 1'Ch |
| Gauge | 4 ft 8½ in (1,435 mm) |
| Leading wheel size | 36 in (0.914 m) |
| Driver size | 63 in (1.600 m) |
| Length | 55 ft 11 in |
| Locomotive weight | 59.1 long tons (60.0 t) |
| Fuel type | Coal |
| Fuel capacity | 4 long tons (4.1 t) |
| Water capacity | 3,500 imp gal (16,000 l) |
| Boiler | LMS 4D |
| Boiler pressure | 225 psi (1.55 MPa) |
| Fire grate area | 23 sq ft (2.1 m²) |
| Cylinders | Two, outside |
| Cylinder size | 17½×26 in (445×660 mm) |
| Valve gear | Walschaerts |
| Tractive effort | 24,170 lbf (107.51 kN) |
| Career | London, Midland & Scottish British Railways |
| Class | LMS: 4F, later 4 BR: 4MT |
| Nicknames | Mucky Ducks |
| Retired | 1963–68 |
The London Midland and Scottish Railway (LMS) Ivatt Class 4 2-6-0 is a class of steam locomotive primarily designed for medium freight work but also widely used on secondary passenger services. 162 were built between 1947 and 1952, but only three were built by the LMS before nationalisation in 1948. Designed by H.G. Ivatt, they were classified 4F by the LMS and 4MT by BR. Even before Nationalisation they ventured beyond the LMS system: they were used extensively on the Midland & Great Northern Railway in East Anglia where they became the dominant locomotive type, and also occasionally on the Somerset & Dorset Joint.
The first three were numbered 3000-2, 40000 being added onto their numbers by BR to become 43000/2, the remaining 159 built by BR receiving the numbers 43003-161. They were also called 'mucky ducks.'
The design was noted for its American looks – with the boilerside footplating at high level and a gap left ahead of the cylinders. Because of this many people considered it to be the ugliest British locomotive produced, especially those versions outshopped with double chimneys: however, these gave poor performance and were quickly replaced with single chimneys. The locomotives also incorporated new mechanical features intended to reduce maintenance costs.
The BR standard class 4 2-6-0 was based on this design. Its looks were improved somewhat by the redesign of the outside footplating to include a sloping plate to fill the gap ahead of the cylinders.
One, 43106, has survived to preservation. Based at the Severn Valley Railway and known as the Flying Pig, it is out of service undergoing a major overhaul that (in May 2008) is well advanced.
Reference: ES Cox, British Railways Standard Steam Locomotives, pages 92/93. ISBN 0-7110-0449-8.
