Professor W A Tuplin (1902-1975) was an engineering academic and specialist in the design of gears. He worked for the vehicle manufacturer David Brown, eventually becoming Chief Engineer before being appointed Professor of Applied Mechanics at Sheffield University until he retired in 1968.
In addition to contributions to journals, Tuplin was the author of many books about steam locomotives, including Midland Steam, Midland Steam, The Steam Locomotive, Great Western Power, Great Western Saints and Sinners and North Eastern Steam, Great Northern Steam, Great Central Steam, Tuplin's large output meant that he was widely read amongst the interested public, but he was not a locomotive engineer. His sometimes controversial opinions brought him into conflict with practising engineers such as E S Cox and Ell, who was responsible for the redesign of the King and Castle classes in the early 1950s. Consequently, his views need to be read with caution, if not taken with a pinch of salt.
However, and subject to that caveat, it is instructive to read Tuplin's comments on particular classes, including some which have been selected as prototypes for replicas. Even the best machines have their weaknesses, and some of the selected replica types are referred to in his writings. Those who are engaged in these projects could usefully comb through Tuplin's observations. It seems pointless to perpetuate faults in brand new locomotives when small modifications could get rid of the defects without affecting their appearance. Some of the proposed replicas might be of designs which would be best left as memories rather than re-created at full size in new metal.