The W~(AB)/W~S Class Steam Locomotives

摘要

In 1916 the New Zealand Railways Chief Mechanical Engineer, H H Jackson, decided that a more powerful tank locomotive than was then available was required for working suburban trains on the steep grades in the Auckland and Wellington areas. He drew up proposals for a tank engine version of the A~B class, then under construction. The proposal was submitted in July 1916 and permission was given by Cabinet to build a prototype using materials from the second batch of A~Bs.The new locomotive was classified as W~(AB) although in the preliminary discussion the class was referred to as W~S. The official photograph of locomotive number 686 taken at Addington shows the classification to be W~S but it was as a W~(AB) that 686 entered service.