boiler was retained, though the Eastleigh superheater was replaced by a Maunsell type with 10 per cent greater superheating surface area. This was supplemented by a larger steam chest and an increased-diameter chimney casting specially designed for the rebuilds. It incorporated a rim and capuchon to control exhaust flow into the atmosphere. Valve events (the timing of valve movements with the piston) were also revised to promote efficient steam usage and the wheels were re-balanced to reduce hammerblow. When rebuilding was complete, only the numbers, smokebox doors with centre tightening handles and the flat-sided cabs remained of the G14 and P14 classes. The rebuilds retained their distinctive Drummond "watercart" tenders, which were modified with the removal of the complex injector feedwater heating equipment. The "watercart" tenders were of water and coal capacity. The ten rebuilds became the first members of the King Arthur class upon entering service. "Scotch Arthurs" As the Drummond G14 and P14 4-6-0s were rebuilt to the N15 specification at Eastleigh, a lack of production capacity due to repair and overhaul meant that Maunsell ordered a further batch of 20 locomotives from the North British Locomotive Company in 1924. The company had under-quoted to gain the contract, which meant that production of the batch was rushed. The necessity to maintain an intensive timetable on the Southern Railway's Western section prompted an increase of the order to 30 locomotives (Nos. E763–E792). Their construction in Glasgow would gain them the "Scotch Arthurs" nickname in service. They were all delivered to the Southern Railway by October 1925, and featured the front-end refinements used on the Drummond rebuilds. The North British batch was built to the Southern's new composite loading gauge and differed from previous batches in having an Ashford-style cab based upon that used on the N class. Unlike the Drummond cab retained by Nos. 448–457 and E741–E755, the Ashford cab was of an all-steel construction and had a roof that was flush with the cab sides, allowing it to be used on gauge-restricted routes in the east of the network. It was inspired by the standard cab developed in 1904 by R. M. Deeley for the Midland Railway, and was one of a number of Midland features introduced by Clayton to the SECR and subsequently the Southern Railway. The smokebox door was revised to the Ashford pattern, which omitted the use of central tightening handles in favour of clamps