| NZR KA class | |
|---|---|
| A streamlined KA class locomotive | |
| Power type | Steam |
| Builder | NZR Hutt Workshops |
| Build date | 1939 - 1945, 1950 |
| Configuration | 4-8-4 |
| Gauge | 3 ft 6 in (1,067 mm) Cape gauge |
| Wheel diameter | 54 in (1.37 m) |
| Wheelbase | 34 ft 10 in (10.62 m) |
| Length | 69 ft 8 in (21.2 m) |
| Width | 8 ft 6 in (2.6 m) |
| Height | 11 ft 6 in (3.5 m) |
| Weight on drivers | 56.4 long tons (57.3 t) |
| Locomotive weight | 93 long tons (94 t) |
| Tender weight | 52.9 long tons (53.7 t) |
| Locomotive & tender combined weight |
145.9 long tons (148.2 t) |
| Fuel type | Coal (original) Oil (converted 1947 - 1953) |
| Fuel capacity | 7.5 long tons (7.6 t) coal 1,570 imp gal (7,100 L) oil |
| Water capacity | 5,000 imp gal (23,000 L) |
| Boiler pressure | 200 psi (1,400 kPa) |
| Feedwater heater | ACFI (KA 930 - 959) |
| Firegrate area | 47.7 square feet (4.4 m2) |
| Heating surface: Total |
1,933 square feet (179.6 m2) |
| Superheater area | 485 square feet (45.1 m2) |
| Cylinders | 2 |
| Cylinder size | 20 × 26 in (51 × 66 cm) |
| Power output | 1,400 hp (1,000 kW) |
| Tractive effort | 30,815 lbf (137.07 kN) |
| Number in class | 35 |
| Number | 930 - 964 |
| Official name | "Nigel Bruce" (KA 942) |
| Locale | North Island of New Zealand |
| First run | 1939 |
| Last run | December 1967 |
| Retired | 1965 - 1967 |
| Restored | 1985 (KA 945) |
| Scrapped | 1966 - 1967 |
| Current owner | Mainline Steam, Silver Stream Railway, Steam Incorporated |
| Disposition | Withdrawn; 3 preserved |
The NZR KA class of 1939 was a class of mixed traffic 4-8-4 steam locomotives that operated on New Zealand's railway network. They were built after the success of the K class to meet the increasing traffic demands of the New Zealand Railways Department. The locomotives first appeared with distinctive streamlining, mainly to hide their ACFI feedwater systems.
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Following the success of the K class, there was a need for more similar locomotives in the North Island. The new locomotives incorporated a number of improvements, including a re-designed plate frame to eliminate the cracking issues the K class were experiencing; roller bearings on all wheels; hydrostatic lubrication throughout; and the inclusion of the ACFI feedwater system as pioneered by K 919. As the ACFI equipment was criticised for its aesthetic appearance, it was obscured with shrouding fitted to both the KA class and contemporary KB class.
Building of the locomotives commenced in 1939, just prior to the Second World War. Main construction and assembly took place at Hutt Workshops. Hillside Workshops largely constructed - but did not assemble - ten of the class (No.’s 940-944, 960-964) and built a further five KA boilers. The primary reason why the ten KAs were not assembled at Hillside was because there was no way of transporting complete locomotives between the North and South Islands at the time (the first Railways Department rail ferry didn't commence until 1962). The Vulcan Foundry, of the United Kingdom supplied parts for fifteen locomotives, including most chassis components, tender bogies, and boiler foundation rings. The General Casting Corporation of Pennsylvania, USA supplied trailing bogie and rear end framing. A company in Auckland also constructed up to 10 tenders for the class. While the imported components were intended for specific locomotives (and in some cases were stamped for the locomotives they were intended for) in practice, and due to wartime pressures, the imported components were used indiscriminately for any KA locomotives in the programme.
Nineteen locomotives were built between 1939 and 1941, but wartime circumstances meant construction of the remaining sixteen lasted from 1941 to 1950, a period much longer than NZR management anticipated. The first of the locomotives to be completed was KA 945. All but two members of the class were constructed by 1946. The final pair, No.'s 958 and 959, differed somewhat from the rest of their class due to being fitted with Baker valve gear instead of the Walschaerts valve gear fitted to all other members, and were oil burners from new. Like some of the other later KAs, they were not built with shrouding, although the front shrouding and many front-end components had been built for KA 959 for display at an exhibition. These were ultimately used on KA 939.
The KA class was solely based in the North Island, and upon entering service, the first members were placed on heavy freight and express passenger service. They saw extensive use on these tasks during wartime. The shrouding, while cleaning up the appearance of the locomotives, was open at the top and began gathering soot and dust that affected the working environment in the cab. After the war, a coal shortage also occurred and NZR decided to convert a large number of locomotives to oil burning. The KA class were a prime candidate due to the large size of the grate. Conversion to oil burning occurred from 1947 and 1953, with nineteen of the class done at Otahuhu Workshops and sixteen at Hutt. The conversion coincided with the removal of the shrouding, and also the replacement of the ACFI feedwater system with an exhaust steam injector.
The locomotives became a mainstay of the North Island motive power fleet, and although primarily seen on the North Island Main Trunk Railway, they also worked other lines, such as the Palmerston North - Gisborne Line as far as Napier and the Stratford - Okahukura Line.
At one stage, KA 944 was sent to the South Island for an overhaul at Hillside Workshops and for subsequent use on the Midland Line along with the KB class. Although it was overhauled, it did not operate on the Midland Line due to union objections and was repatriated back to the North Island.
One member of the class, KA 949, was wrecked in the Tangiwai disaster on 24 December 1953, New Zealand’s worst rail disaster. Although recovered from the Whangaehu River and taken to Hutt Workshops, it was never repaired and officially written off in 1955. Although the locomotive was subsequently scrapped, the NZR recovered quite a number of components from it and re-used these on other locomotives as the need arose.
With the commencement of main line dieselisation in 1954, the class was slowly displaced from front line service, especially as the DA class was progressively introduced to service from 1955. Withdrawals began in 1964. The last locomotive in revenue service, KA 935, ran in 1967. KA 942 was held for a time at Hutt Workshops for possible use as a stationery boiler, but this did not proceed.
Three of the KA class have been preserved:
KA 935 was preserved by the Wellington Branch of the New Zealand Railway & Locomotive Society in 1967, and was initially stored at the Waikato Railway Museum in Te Awamutu until the site at Seaview, Lower Hutt where a railway was being established. Later KA 935 moved along with the rest of the collection to the new site at the Silver Stream Railway in 1984, being moved there in steam behind a diesel towing the rest of the items. Since that time KA 935 has remained at Silverstream, and is currently out of service awaiting a 10-year overhaul. Due to the short nature of the Silver Stream Railway, 935 has been converted from superheating to a saturated state by removal of the superheater elements.
KA 942 was preserved by Ian Welch in 1972, after having been laid up at Hutt Workshops as a possible addition to 3 K Class locomotives being used as a stationary boiler supply. It was moved to Steam Incorporated and some limited work was done on restoring it, however by the mid-1980's it had been moved to Otaki for open air storage. In 1989 it was moved to the Glenbrook Vintage Railway where it was restored to working order, and main line certified - first running from 1991, wearing its former streamline shrouding. Initially based out of Mainline Steam's Parnell depot, it alternated between Parnell and Christchurch before being moved to Wellington in 2001 so that a comprehensive 10-year overhaul could be conducted. KA 942 returned to service in 2008.
KA 945 was preserved by Len Southward (who created the Southward Car Museum, who had it stored in Taumaranui at first and then later at Steam Incorporated, Paekakariki. Later he gifted KA 945 to Steam Incorporated, and they began slowly overhauling it to working order. In late 1984, the pace of work accelerated to have it ready in time for the return of steam to the main line in 1985, a goal which was achieved. In the 10 years that followed KA 945 ran numerous excursions all over the country, including the Crunchie Train Tour of 1993. In 1995 it was withdrawn for a 10-year overhaul, however due to a number of constraints this has not taken place yet.
| Key: | In service | Out of service | Auckland Transport service | Preserved | Overhaul | Scrapped |
|---|
| Number | Builder | Introduced[1] | Withdrawn[1] | Notes |
|---|---|---|---|---|
| 930 | NZR Hutt | March 1940 | October 1966 | |
| 931 | NZR Hutt | May 1940 | April 1966 | |
| 932 | NZR Hutt | May 1940 | May 1967 | |
| 933 | NZR Hutt | July 1940 | October 1966 | |
| 934 | NZR Hutt | August 1941 | October 1966 | |
| 935 | NZR Hutt | October 1941 | December 1967 | Donated by NZR to Wellington Branch of the NZR&LS. Preserved by Silver Stream Railway; stored awaiting a boiler overhaul (10-year). |
| 936 | NZR Hutt | February 1942 | January 1966 | |
| 937 | NZR Hutt | November 1943 | November 1967 | |
| 938 | NZR Hutt | December 1943 | July 1964 | |
| 939 | NZR Hutt | March 1944 | January 1965 | Tender from this locomotive preserved by Mainline Steam, Parnell |
| 940 | NZR Hutt | September 1940 | December 1965 | |
| 941 | NZR Hutt | October 1940 | December 1967 | |
| 942 | NZR Hutt | November 1940 | August 1967 | Purchased 1972 by Ian Welch for Mainline Steam and named Nigel Bruce; restored and certified for main line use. Usually partially streamlined/shrouded, since November 2010 the locomotive has been de-streamlined and temporarily renumbered 949 for use in a documentary about the Tangiwai Disaster. |
| 943 | NZR Hutt | February 1941 | May 1967 | |
| 944 | NZR Hutt | May 1941 | December 1965 | |
| 945 | NZR Hutt | July 1939 | December 1967 | Purchased from NZR by Len Southward for Southward Car Museum; donated to Steam Incorporated, restored and in use on the main line from 1985; currently stored dismantled, awaiting overhaul. |
| 946 | NZR Hutt | August 1939 | January 1965 | |
| 947 | NZR Hutt | August 1939 | May 1966 | |
| 948 | NZR Hutt | August 1939 | May 1966 | |
| 949 | NZR Hutt | October 1939 | March 1955 | Wrecked in the Tangiwai disaster on 24 December 1953; officially written off March 1955. |
| 950 | NZR Hutt | November 1939 | December 1965 | |
| 951 | NZR Hutt | November 1939 | March 1965 | |
| 952 | NZR Hutt | December 1939 | October 1966 | |
| 953 | NZR Hutt | July 1944 | May 1967 | |
| 954 | NZR Hutt | October 1944 | September 1966 | |
| 955 | NZR Hutt | December 1944 | May 1967 | |
| 956 | NZR Hutt | September 1945 | October 1966 | |
| 957 | NZR Hutt | April 1946 | October 1966 | |
| 958 | NZR Hutt | February 1950 | February 1967 | Baker Valve Gear |
| 959 | NZR Hutt | March 1950 | October 1966 | Baker Valve Gear |
| 960 | NZR Hutt | March 1939 | September 1966 | |
| 961 | NZR Hutt | April 1940 | September 1966 | |
| 962 | NZR Hutt | April 1940 | September 1966 | |
| 963 | NZR Hutt | August 1940 | October 1966 | |
| 964 | NZR Hutt | June 1941 | October 1966 |