LMS Ivatt Class 4MT - Gateway to the LMS

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Ivatt Class 4F/4MT
Class 4MT no. 43106 at Kidderminster, Severn Valley Railway, 31st December, 2013
Technical Data
Introduced : 1947
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 opinion 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) currently operational and based on the Severn Valley Railway.
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