sentences:  By 1923, the eight-wheeled tenders had been replaced by six wheeled 3,500 gallon (15.9m3) versions transferred from K10 and L11 locomotives.After Drummond's death, Robert Urie, his successor, fitted the class with Eastleigh superheaters.These had a very small superheating surface so they were replaced by Maunsell superheaters, when Richard Maunsell was appointed Chief Mechanical Engineer of the Southern Railway after the grouping of 1923.