NZR U class

The NZR U class, the first tender locomotives built in New Zealand, were a class of 4-6-0 Ten Wheeler locomotive designed to the requirements of Mr T. F. Rotherham and built at NZR Addington between 1894 and 1903. They were amongst NZRs' longest lived tender engines.
Origin and Design
The U class was designed to fill a need to provide more powerful and faster passenger locomotives than the N and V classes then in service. The class were the first express locomotives on the NZR to have Walschaerts valve motion and also introduced the 4' 6" driving wheel which would be considered standard for express passenger work. They did however have flat slide valves and would be the last NZR locomotives so built.
The U's were the first tender locomotives built in New Zealand and were a significant step in the country's industrial capability. However, Addington was not yet set up for mass production and construction was intermittent and drawn out, resulting in changes...