sentences:  The result of these failures was that when he designed what was to be his last class in 1911, a new 4-4-0 design emerged from Eastleigh Works in February 1912, with what was to be the first of his D15 class.In line with the typical Drummond layout, the D15s had a short smokebox with wing plates.The boiler was based on that fitted to the 1905 rebuild of his first double-single, T7 class number 720 of 1897; and had a long firebox with a sloping grate.