Ivatt Class 4F/4MT
Technical Data
Introduced: 1947
Number built: 162 (3 built by the LMS, the remainder being built by British Railways)
Wheel arrangement: 2-6-0
Number built: 162 (3 built by the LMS, the remainder being built by British Railways)
Wheel arrangement: 2-6-0
A post-war design (in fact, this was the last LMS steam locomotive design) intended as a replacement for older freight locomotives, the look of this locomotive owes a lot to the American class S160 locomotives used during the Second World War, particularly with a high running plate leaving the wheels completely exposed. The locomotive was designed for ease of use and ease of maintenance, post-war conditions meaning that designers had to take more note of the human element of locomotive operation, something that had been perhaps lacking in the designs prior to 1945. Initially the class suffered from steaming issues caused by the exhaust arrangement; mainly due to the double chimneys installed on the first examples built. However, by 1951, the issues had been ironed out, particularly by replacing the double chimney with a single one, and the locomotives proved very capable from this point on, the last withdrawal taking place in 1968, over twenty years after the first one was built.
They were perhaps not the most aesthetically pleasing of locomotives, with some opinions saying that they were the most ugly locomotives after the Southern Railway's Q1 freight locomotives introduced during World War II (One nickname given to the class was "Flying Pigs"). However, this was a time when aesthetics sometimes had to take a back seat to functionality and economy, and personally I quite like the design and am always happy to travel behind 43106.
The Ivatt designs could often be found outside the London Midland Region of British Railways, and the 4MT was also used on the Eastern and North Eastern Regions as well. The design eventually evolved into the 76XXX class of British Railway Standard Locomotives.
Number | Works Built at | Year Built |
3000-3002 | Horwich | 1947 |
43003-43022 | Horwich | 1948 |
43023-43049 | Horwich | 1949 |
43050-43069 | Doncaster | 1950 |
43070-43096 | Darlington | 1950 |
43097-43106 | Darlington | 1951 |
43107-43111 | Doncaster | 1951 |
43112-43135 | Horwich | 1951 |
43136 | Horwich | 1952 |
43137-43155 | Doncaster | 1951 |
43156-43161 | Doncaster | 1952 |
Preservation
Only one example survives: no. 43106 (as previously mentioned), which is based on the Severn Valley Railway and is currently awaiting an overhaul.