When that company was nationalised in 1908, they passed into the ownership of the New Zealand Railways and received the designation UD.

[2] The two locomotives were the final new motive power ordered by the independent Wellington and Manawatu Railway Company.

The 58 inches (1,473 mm) coupled driving wheels were large for the period, [2] and were the largest to run in New Zealand.

The handsome UD locomotives were more than capable of making up lost time, with mile-a-minute runs recalled with pride by Manawatu railway employees.

[3] Although they were fast and powerful, the UD locomotives were unable to survive a programme of standardisation undertaken between 1925 and 1935 to eliminate small locomotive classes that were costly to maintain in favour of large, homogeneous types that provided economies of scale.