I'd say that the Chief Draughtsman would probably be well read in technical papers of the time, the Pearson version some 5 years later thanks to Bruce, showing that Pearson on this side of the world pushed the envelope, but failed to get it right and went to his design of the Walschaert gear. Reinvented again in 1913 and perfected I guess, question begs did the "Southern" inventor read very old trade publications to start with perhaps?.
New Zealand Railways had a number of prominent developments in the Steam era, Pearson favoured the use of Piston valves and Walschaert years before others, achieving 1HP per Ton of Locomotive was another.
Further reading of this [
nzetc.victoria.ac.nz] will reveal more than this Diesel boy remembers.Quote: "
while it would not perhaps be correct to say that locomotive designers elsewhere knowingly copied New Zealand work, it is undoubtedly true that the New Zealand designer was definitely in advance of progress elsewhere."