# NZR UD class

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Class of 2 New Zealand 4-6-0 locomotives

NZR UD class Ud Class no 464 between 1909 and 1929 Type and origin Power type Steam Builder Baldwin Locomotive Works Build date 1904 Total produced 2 Specifications Configuration: ​ • Whyte 4-6-0 Gauge 3 ft 6 in (1,067 mm) Driver dia. 58 in (1,473 mm) Adhesive weight 29.2 long tons (29.7 t; 32.7 short tons)[1] Loco weight 39.5 long tons (40.1 t; 44.2 short tons) Tender weight 27.4 long tons (27.8 t; 30.7 short tons) Fuel type Coal Water cap. 2,400 imp gal (11,000 L; 2,900 US gal) Tender cap. 5 long tons (5.1 t; 5.6 short tons) Firebox: ​ • Grate area 16.5 sq ft (1.53 m2) Boiler pressure 185 psi (1,276 kPa) Heating surface 1,095 sq ft (101.7 m2) Cylinders 2 Cylinder size 16.5 in × 22 in (419 mm × 559 mm) Valve gear Stephenson Performance figures Tractive effort 15,280 lbf (68.0 kN) Career Number in class 2 Retired 1929

The **NZR UD class** was a class of two [4-6-0](/source/4-6-0) [steam locomotives](/source/Steam_locomotive) built by the [Baldwin Locomotive Works](/source/Baldwin_Locomotive_Works) in 1904 for the [Wellington and Manawatu Railway Company](/source/Wellington_and_Manawatu_Railway_Company). When that company was nationalised in 1908, they passed into the ownership of the [New Zealand Railways](/source/New_Zealand_Railways_Department) and received the designation UD.[2]

## Introduction

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

## Specification

Weighing 39.5 long tons (40.1 t; 44.2 short tons) with a [tender](/source/Tender_(rail)) of 27.4 long tons (27.8 t; 30.7 short tons), they could haul express trains easily at 50 miles per hour (80 km/h) on track that was flat or only a light grade. The 58 inches (1,473 mm) coupled driving wheels were large for the period, [2] and were the largest to run in New Zealand.[3][4] Their working steam pressure was 185 pounds per square inch (1,276 kPa), and they had 16.5 inches (419 mm) [diameter](/source/Diameter) cylinders with 22 inches (559 mm) [piston strokes](/source/Stroke_(engine)).

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.[2] Due to their power, the locomotives were capable of hauling mail trains without the need for a banking locomotive from Paekakariki south to Pukerua Bay,[5] and were used principally on mail trains north of Paekakariki.[3]

## Withdrawal

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. They were written off in 1929.

## References

### Citations

1. **[^](#cite_ref-FOOTNOTECassells1994169_1-0)** [Cassells 1994](#CITEREFCassells1994), p. 169.

1. ^ [***a***](#cite_ref-FOOTNOTEPalmerStewart196598_2-0) [***b***](#cite_ref-FOOTNOTEPalmerStewart196598_2-1) [***c***](#cite_ref-FOOTNOTEPalmerStewart196598_2-2) [***d***](#cite_ref-FOOTNOTEPalmerStewart196598_2-3) [Palmer & Stewart 1965](#CITEREFPalmerStewart1965), p. 98.

1. ^ [***a***](#cite_ref-FOOTNOTECassells1994108_3-0) [***b***](#cite_ref-FOOTNOTECassells1994108_3-1) [Cassells 1994](#CITEREFCassells1994), p. 108.

1. **[^](#cite_ref-FOOTNOTEHoy197270_4-0)** [Hoy 1972](#CITEREFHoy1972), p. 70.

1. **[^](#cite_ref-FOOTNOTECassells1994122_5-0)** [Cassells 1994](#CITEREFCassells1994), p. 122.

### Bibliography

- Cassells, KR (Ken) (1994). *Uncommon Carrier - The History of the Wellington & Manawatu Railway Company, 1882-1908*. [New Zealand Railway and Locomotive Society](/source/New_Zealand_Railway_and_Locomotive_Society). [ISBN](/source/ISBN_(identifier)) [0908573634](https://en.wikipedia.org/wiki/Special:BookSources/0908573634).

- Hoy, Douglas (1972). *West of the Tararuas: An Illustrated History of the Wellington and Manawatu Railway Co*. Dunedin: Southern Press.

- Millar, Sean (2011). *The NZR Steam Locomotive*. Wellington: [New Zealand Railway and Locomotive Society](/source/New_Zealand_Railway_and_Locomotive_Society). [ISBN](/source/ISBN_(identifier)) [978-0-908573-89-9](https://en.wikipedia.org/wiki/Special:BookSources/978-0-908573-89-9).

- Palmer, A. N.; Stewart, W. W. (1965). *Cavalcade of New Zealand Locomotives*. Wellington: [A H. & A W. Reed](/source/Reed_Publishing). [ISBN](/source/ISBN_(identifier)) [978-0-207-94500-7](https://en.wikipedia.org/wiki/Special:BookSources/978-0-207-94500-7).

- Stewart, W. W. (1974). *When Steam was King*. Wellington: [A. H. & A. W. Reed Ltd](/source/Reed_Publishing). [ISBN](/source/ISBN_(identifier)) [978-0-589-00382-1](https://en.wikipedia.org/wiki/Special:BookSources/978-0-589-00382-1).

## External links

- [Photo of 1910 derailment](https://kura.aucklandlibraries.govt.nz/digital/collection/photos/id/195531) at [Koputaroa](/source/Koputaroa_railway_station)

v t e Rail vehicles of New Zealand Diesel locomotives Mainline DA (inc. DAA, DAR) DB (inc. DBR) DC (inc. DCP) DF (English Electric) DF (General Motors) inc. DFT, DFB, DFM DG (inc. DH of 1956) DI DJ DL DM DQ and QR DX (inc. DXB, DXC, DXR) Shunt DE DH of 1978 DS DSA DSB DSC DSG DSH (on order) DSJ TR Electric locomotives 1500 V DC EA (later EO of 1968) EC ED EO of 1923 EW 25 kV AC EF Battery E EB Diesel multiple units ADK/ADB class diesel multiple unit ADL/ADC class diesel multiple unit Electric multiple units 1500 V DC (Wellington) "English Electric" DM (inc. D trailers) "Ganz Mavag" EM (inc. ET trailers) "Matangi" FP (inc. FT trailers) "Tūhono" BEMU (on order) 25 kV AC (Auckland) AM (inc. AMP, AMT, AMA) Railcars RM class 88 seater (also known as Fiats or twinsets) Clayton steam railcar Edison battery-electric railcar Red Terror railcar Midland railcar Leyland experimental petrol railcar McEwan Pratt petrol railcar Model T Ford railcar Sentinel-Cammell steam railcar Silver Fern railcar Standard railcar Thomas Transmission railcar Vulcan railcar Wairarapa railcar Westinghouse railcar Others A 88 Buckhurst petrol carriage Steam locomotives A of 1873 A of 1906 (inc. AD) AA AB B of 1874 B of 1899 BA BB BC C of 1873 C of 1930 D of 1874 D of 1929 E of 1872 & 1875 E of 1906 F FA (inc. FB) G of 1874 G Garratt of 1928 (inc. Pacific rebuild) H J of 1874 J of 1939 JA JB K of 1877 K of 1932 KA KB L LA M N NA NC O OA OB OC P of 1876 P of 1885 Q of 1878 Q of 1901 R S T U UA UB UC UD V W WA WAB WB WD WE WF WG WH WJ WS WW X Y Locomotive hauled carriages 50-foot carriage 56-foot carriage AC class (Grassgrubs) ex-British Rail Mark 2 carriage AK carriage FM class guards van SX carriages Track evaluation, cranes, and maintenance ETM class track evaluation car EL class rail cranes ETM class rail maintenance equipment Locomotives of New Zealand Rail transport in New Zealand Railway preservation in New Zealand.

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Adapted from the Wikipedia article [NZR UD class](https://en.wikipedia.org/wiki/NZR_UD_class) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/NZR_UD_class?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.