Wainwright D class engines for similar engine built in the same year. That photo is from the 'Mike Morant collection'.
And, shown here on the left is the same type of locomotive in wartime black livery with Bulleiud's so-called 'sunshine character' style. The picture was taken at Ashford in Kent immediately after the war and prior to Aug 1949 when engine No 1057 became 31057. - This information and the photo is shown with thanks to the 'Mike Morant collection'.