The NZR D class of 1929 comprised one 0-4-0 tank locomotive that was built for the New Zealand Railways Department by the Clayton Wagons Ltd in Lincoln, England.

It had a White-Forster type boiler designed for a working pressure of 300 psi (2,068 kPa), had four vertical cylinders housed in the rear of the cab and was high geared.

At a normal engine speed of 400 rpm, the unit was calculated to develop 200 horsepower (150 kW).

On arrival in New Zealand, D 1 was found to be more than 25 percent heavier than the specified maximum of 20 long tons (20.3 t; 22.4 short tons) and after trials in Wellington was allocated for use as a shunting engine at the Ōtāhuhu workshops.

However it never proved satisfactory and was written off in 1936 and scrapped and D 1 did not survive to be preserved.