A Maunsell Lord Nelson 4-6-0 7P post-1939 enginespec. These locos were designed to haul 550tons at 55mph start-to-stop.
This spec has the steam chest volume at 2.0 times cylinder volume, and piston-vol-min at 2 times the Attewell data. Boiler-heat-loss reduced to 1.2 (poss Gj/h). MFC = 0.05, ADC 0.02