Mr. Mack was the first controller of the Skarloey Railway. When he retired, he was succeeded by Mr. Peter Sam.
He did not know much about engines' feelings and after failing time and time again to steam Skarloey, he lost patience and covered him up with a tarpaulin. Later, while travelling on Skarloey, he was knocked into a bush after he closed Skarloey's regulator too quickly and he rode in Beatrice for the remainder of the journey. However, Mr. Mack did gain patience after he brought Mr. Bobbie to be Skarloey's driver. He then arranged for Skarloey to have an extra set of wheels and be rebuilt with a cab.