NZR D class (1929)

NZR D class
Trial run of Clayton D class locomotive No 1 at Silverstream
Type and origin Builder Clayton(1) Build date 1929
Specifications Configuration: ​  • Whyte 0-4-0 Driver dia. 42 Loco weight 25.7 long tons (26.1 t; 28.8 short tons) Firebox:  • Firegrate area 12.5 sq ft (1.16 m2) Boiler pressure 300 lbf/in2 (2.07 MPa) Heating surface 320 sq ft (30 m2) Cylinders 4, vertical Cylinder size 7 in × 10 in (178 mm × 254 mm)
Career Operators 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 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). 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 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 Otahuhu workshops. However it never proved satisfactory and was written off in 1936 and scrapped and D 1 did not survive to be preserved.