Ivatt Class 4MT 3000 LMS Black Double Chimney
Built: 1947 – 1952
Built for: LMS/ BR
Designed by: Henry G. Ivatt
Duties: mixed traffic
• Double chimney variant
• Elaborate construction with high running plate and all external pipework modelled
• Sprung buffers
• Removable coal load with empty coal space modelled below
These were the last locomotives designed and built by the LMS and the unconventional design was influenced by the successful use of American S160 locomotives during the 2nd World War. Designed for ease of maintenance rather than aesthetics, they were constructed with a high mounted boiler and running plate for quick access to pipe work and auxiliary fittings, with the result that they soon earned the nicknames ‘Flying Pig’ and ‘Mucky Duck’.
A total of 162 of these popular and versatile mixed traffic locomotives were built between 1947 and 1952 and worked across the London Midland, Eastern and Scottish Regions. The first 50 were built with a double chimney, which caused exhaust problems. The remainder of the batch was improved by fitting a single chimney and by 1952 the first fifty were all modified and fitted with the same chimney.
With a cut-down tender and enclosed cab, the locomotives could be easily driven tender first, making them suitable for routes without turntables. They proved to be a very powerful and reliable locomotive, well suited to secondary passenger services and general freight duties. BR started to withdraw these locomotives in 1963 but the last of these moguls survived until the very end of main line BR steam in August 1968. Loco 43106 survives in preservation.