| NZR D class | |
| Builder: | Clayton(1) |
| Builddate: | 1929 |
| Whytetype: | 0-4-0 |
| Driverdiameter: | 42 |
| Locoweight: | 25.71NaN1 |
| Boilerpressure: | 3002NaN2 |
| Firearea: | 12.5square feet |
| Totalsurface: | 320square feet |
| Cylindercount: | 4, vertical |
| Cylindersize: | 7x |
| Operator: | NZR |
| Disposition: | Scrapped |
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.
Originally, D 1 was purchased for railcar type service but it was not successful. It had a White-Forster type boiler designed for a working pressure of 300psi, 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 . The engine drove a central transverse jackshaft through reduction gearing, the drive from the jackshaft being transmitted to the wheels through conventional side rods.
On arrival in New Zealand, D 1 was found to be more than 25 percent heavier than the specified maximum of 20LT 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.