|The Ab class was introduced in 1915 and was designed to the requirements of H. H. Jackson by the Chief Draughtsman, S. H. Jenkinson. It was a simple, superheated Pacific's featuring the cylindrical Vanderbilt tender. Jackson had been impressed with these tenders on a visit to America and it was adopted because of its light weight and economy of construction.
Originally the Ab handled all principal express services and main-line freight services, until the advent of the K's and J's when they were relegated to to freight haulage on branch and secondary lines. They were rated to haul 700 - 750 tons on easy grades. Every district, except Wellington, had a quota of Ab's. Both the North and South Island had the Ab.
The Ab locomotives handled all types of services, on main lines, secondary routes and branch lines. Until the 1930's they were the main express and freight locomotive for both islands, and could handle 700 tons on easy grades. Many were transferred to the South Island from the 1950's and even as late as the 1960's, an Ab would be used on express workings. Ab663 was the first Ab to reach Auckland, replacing the A class Pacific's on the express train duties and had the honour of hauling the Royal train for the Prince of Wales out of Auckland in 1920.
It mainly worked on the Main Trunk, based at Taumarunui, where it would have made many an ascent of the Raurimu Spiral. Ab663 was largely superseded by the K class locomotives in the 1930's, but continued to work assisting trains and on lighter train duties.
In September 1959 Ab663 was transferred to the South Island and after overhaul at Hillside workshops it was based in Dunedin working the South Island main trunk, the Otago Central railway and the many other branch lines. It was also based at Christchurch for a time, and finished its days on the West Coast. It was withdrawn from service in July 1969.
From 1969 it was stored at the Elmer Lane depot with A428 and in the 1970's it was transferred to Invercargill and stripped of parts for the Kingston Flyer locomotives.
It was purchased in 1983 by Ian Welch in a , as is where is, condition and moved to Wellington in 1984. As 663 had lost its tender some time before it was united with the tender from Ab 811. Restoration was commenced in the Carpenters Shop of the NZR Hutt Workshops in 1988 and when these premises were demolished in the early 1990's, the locomotive was moved to the Silverstream Railway Museum near Upper Hutt where the restoration was completed. The locomotive was also converted from being coal fired to oil fired. The restoration was completed in May 1997 and was named Sharon Lee after Ian Welch's youngest daughter.
Its first Mainline excursion took place in June 1997 when it ran from Wellington to Taumarunui to join J1211 for a Double Drivers excursion.
FURTHER READING The Story of Mainline Steam by Jo Evans
Cavalcade of New Zealand Locomotives - A N Palmer & W W Stewart
Register of New Zealand Railway Steam Locomotives 1863 - 1971 - W G Lloyd