When the intensive suburban service of 1920 was introduced reliance was still placed largely on these 0-6-0s to maintain the new split-second timings, and they were quite equal to the task. By then their numbers had been further reinforced by the twenty built in 1900 and 1901 with 160 lbf/in² (1.1 MPa) boilers, and by a further twenty turned out in 1904, the latter with 180 lbf/in² (1.24 MPa) pressure, larger boilers giving 988 sq ft (91.8 m2) heating surface and 14.5 sq ft (1.35 m2) grate area, and side-tanks holding 1,200 gallons (5,500 L), which increased the weight to 42½ long tons (43 t). Those built from 1912 onwards were decorated with flared-top chimneys, in place of stovepipes, and the high-roofed cab with side-windows which was now the Holden standard.