NZR Kb class
Encyclopedia
The NZR
KB class of 1939 was a class of mixed traffic steam locomotive
s that operated on New Zealand
's railway network
. They were built by the New Zealand Railways Department
(NZR) after the success of the K class
to meet the increasing traffic demands on the Midland Line
in the South Island
. The locomotives had a wheel arrangement
of 4-8-4
and first appeared with distinctive streamlining, mainly to hide their ACFI feedwater systems.
, there was a need for similar locomotives to operate the Midland Line
, primarily between Springfield
and Arthur's Pass
. These new locomotives incorporated a number of improvements upon the K class, including a re-designed plate frame
to eliminate cracking issues the K class experienced; roller bearings
on all wheels; hydrostatic lubrication throughout; and the inclusion of the ACFI feedwater system that had been pioneered on K 919. The ACFI equipment's aesthetic appearance had been criticised, hence the KB and contemporary KA
classes were both fitted with shrouding to obscure it.
The KB class were technically very similar to the KA class, but were distinguished by the inclusion of a booster on the rear axle of the trailing bogie
and Nicholson thermic syphon
s in the firebox. The use of the booster, first proposed for the K class in 1932, was mainly due to steeper gradients and heavy freight trains on the Midland Line, especially Cass
bank. Additional piping and sanding equipment for the booster gave the KB a slightly different appearance to the KA. The booster was intended solely for use at low speed, and some class members ultimately had the booster removed due to problems such as jamming in gear, reducing the locomotive's top speed.
Building of the locomotives commenced in 1939. Construction and assembly took place at NZR's Hillside Workshops. The first of the six member class was produced before the first of the KA class then under construction at Hutt Workshops
. All of the class were in service by 1940.
. However, during the Second World War, they were also used on the Main South Line
.
While the aesthetic shrouding cleaned up the appearance of the locomotives, it was open at the top and gathered soot and dust which affected the working environment in the cab. After the war, the aesthetic shrouding was removed from the locomotives and the ACFI feedwater system was replaced with an exhaust steam injector
.
Although the K and KA classes were converted to burn oil at the time, the KBs remained as coal burners due to the availability of high grade West Coast
coal.
impacted the utilisation of the KB class. This became especially pronounced in the 1960s, and the introduction of the DJ class
in 1968 brought about their ultimate demise. As they were displaced from duties in the late 1960s, some members were used on the Main South Line, including hauling the South Island Limited
.
The first withdrawals were KBs 966 and 969 in October 1967; both were cut up for scrap. KB 969 was withdrawn after hauling the only ever double-headed
KB train, having suffered a cracked motion bracket. Before it was sent to the breakers' yard, it was incribed with a message reading "Goodbye Kb 969, you'll come back as roofing iron
".
KB 967 was withdrawn in October 1968. This left only three KB's in service (965, 968 and 970), and of those, only 968 was serviceable; the remaining two were withdrawn by March 1969. 968 made its last journey on 22 June 1969, hauling a railway enthusiast's excursion from Christchurch to Arthur's Pass and return.
. It is currently under restoration to main line operating condition at Mainline Steam
's Christchurch depot.
New Zealand Railways Department
The New Zealand Railways Department, NZR or NZGR and often known as the "Railways", was a government department charged with owning and maintaining New Zealand's railway infrastructure and operating the railway system. The Department was created in 1880 and was reformed in 1981 into the New...
KB class of 1939 was a class of mixed traffic steam locomotive
Steam locomotive
A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...
s that operated on New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
's railway network
Rail transport in New Zealand
Rail transport in New Zealand consists of a network of gauge railway lines in both the North and South Islands. Rail services are focused primarily on freight, particularly bulk freight, with limited passenger services on some lines...
. They were built by the New Zealand Railways Department
New Zealand Railways Department
The New Zealand Railways Department, NZR or NZGR and often known as the "Railways", was a government department charged with owning and maintaining New Zealand's railway infrastructure and operating the railway system. The Department was created in 1880 and was reformed in 1981 into the New...
(NZR) after the success of the K class
NZR K class (1932)
The NZR K class of 1932 was a class of mixed traffic 4-8-4 steam locomotives that operated on New Zealand's railway network. The locomotives were developed following the failure of the G class Garratts...
to meet the increasing traffic demands on the Midland Line
Midland Line, New Zealand
The Midland line is a 212 km section of railway between Rolleston and Greymouth in the South Island of New Zealand. The line features five major bridges, five viaducts and 17 tunnels, the longest of which is the Otira tunnel.-Freight services:...
in the South Island
South Island
The South Island is the larger of the two major islands of New Zealand, the other being the more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, to the south and east by the Pacific Ocean...
. The locomotives had a wheel arrangement
Wheel arrangement
In rail transport, a wheel arrangement is a system of classifying the way in which wheels are distributed beneath a locomotive.. Several notations exist to describe the wheel assemblies of a locomotive by type, position, and connections, with the adopted notations varying by country...
of 4-8-4
4-8-4
Under the Whyte notation classification of steam locomotives, 4-8-4 represents the wheel arrangement of four leading wheels on two axles , eight powered and coupled driving wheels on four axles, and four trailing wheels on two axles .Other equivalent classifications are:UIC classification: 2D2...
and first appeared with distinctive streamlining, mainly to hide their ACFI feedwater systems.
History
Following the success of the K class in the North IslandNorth Island
The North Island is one of the two main islands of New Zealand, separated from the much less populous South Island by Cook Strait. The island is in area, making it the world's 14th-largest island...
, there was a need for similar locomotives to operate the Midland Line
Midland Line
Midland Line refers to the following rail lines:*Midland railway line, Perth, Australia*Midland Line, New Zealand*Midland Line in Massachusetts, United States...
, primarily between Springfield
Springfield, New Zealand
Springfield is a small town in the Selwyn District of Canterbury, in the South Island, of New Zealand. In 2001 it had a population of 219. At the foot of the Southern Alps, west of Christchurch, it is the most westerly town of the central Canterbury Plains...
and Arthur's Pass
Arthur's Pass
Arthur's Pass is a mountain pass in the Southern Alps of the South Island of New Zealand. It marks part of the boundary between the West Coast and Canterbury regions, 140 km from Christchurch and 95 km from Greymouth. The pass lies in a saddle between the valleys of the Otira River, a...
. These new locomotives incorporated a number of improvements upon the K class, including a re-designed plate frame
Locomotive frame
A locomotive frame is the structure that forms the backbone of the railway locomotive, giving it strength and supporting the superstructure elements such as a cab, boiler or bodywork. The vast majority of locomotives have had a frame structure of some kind...
to eliminate cracking issues the K class experienced; roller bearings
Rolling-element bearing
A rolling-element bearing, also known as a rolling bearing, is a bearing which carries a load by placing round elements between the two pieces...
on all wheels; hydrostatic lubrication throughout; and the inclusion of the ACFI feedwater system that had been pioneered on K 919. The ACFI equipment's aesthetic appearance had been criticised, hence the KB and contemporary KA
NZR Ka class
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...
classes were both fitted with shrouding to obscure it.
The KB class were technically very similar to the KA class, but were distinguished by the inclusion of a booster on the rear axle of the trailing bogie
Bogie
A bogie is a wheeled wagon or trolley. In mechanics terms, a bogie is a chassis or framework carrying wheels, attached to a vehicle. It can be fixed in place, as on a cargo truck, mounted on a swivel, as on a railway carriage/car or locomotive, or sprung as in the suspension of a caterpillar...
and Nicholson thermic syphon
Thermic syphon
Thermic siphons are heat-exchanging elements in the firebox or combustion chamber of some steam boiler and steam locomotive designs. As they are directly exposed to the radiant heat of combustion, they have a high evaporative capacity relative to their size...
s in the firebox. The use of the booster, first proposed for the K class in 1932, was mainly due to steeper gradients and heavy freight trains on the Midland Line, especially Cass
Cass, New Zealand
Cass is a locality in the Selwyn District of the Canterbury region in New Zealand's South Island.It is named for Thomas Cass, an important pioneer surveyor in the area. State Highway 73 passes near the town, and the Midland Line between Christchurch and the West Coast was opened to the town in...
bank. Additional piping and sanding equipment for the booster gave the KB a slightly different appearance to the KA. The booster was intended solely for use at low speed, and some class members ultimately had the booster removed due to problems such as jamming in gear, reducing the locomotive's top speed.
Building of the locomotives commenced in 1939. Construction and assembly took place at NZR's Hillside Workshops. The first of the six member class was produced before the first of the KA class then under construction at Hutt Workshops
Hutt Workshops
The Hutt Railway Workshops is a major railway engineering facility in the Lower Hutt suburb of Gracefield in the Wellington region of New Zealand’s North Island...
. All of the class were in service by 1940.
In service
As intended, the KB class were based solely in the South Island and performed most of their work hauling freight trains on the Midland LineMidland Line
Midland Line refers to the following rail lines:*Midland railway line, Perth, Australia*Midland Line, New Zealand*Midland Line in Massachusetts, United States...
. However, during the Second World War, they were also used on the Main South Line
Main South Line
The Main South Line, sometimes referred to as part of the South Island Main Trunk Railway, is a railroad line that runs north and south from Lyttelton in New Zealand through Christchurch and along the east coast of the South Island to Invercargill via Dunedin...
.
While the aesthetic shrouding cleaned up the appearance of the locomotives, it was open at the top and gathered soot and dust which affected the working environment in the cab. After the war, the aesthetic shrouding was removed from the locomotives and the ACFI feedwater system was replaced with an exhaust steam injector
Injector
ʎ̩An injector, ejector, steam ejector, steam injector, eductor-jet pump or thermocompressor is a pump-like device that uses the Venturi effect of a converging-diverging nozzle to convert the pressure energy of a motive fluid to velocity energy which creates a low pressure zone that dɯaws in and...
.
Although the K and KA classes were converted to burn oil at the time, the KBs remained as coal burners due to the availability of high grade West Coast
West Coast, New Zealand
The West Coast is one of the administrative regions of New Zealand, located on the west coast of the South Island, and is one of the more remote and most sparsely populated areas of the country. It is made up of three districts: Buller, Grey and Westland...
coal.
Withdrawal and disposal
From the mid-1950s, dieselisationDieselisation
Dieselisation or dieselization is a term generally used for the increasingly common use of diesel fuel in vehicles, as opposed to gasoline or steam engines.-Water Transport:...
impacted the utilisation of the KB class. This became especially pronounced in the 1960s, and the introduction of the DJ class
NZR DJ class
The NZR DJ class locomotive is a class of diesel-electric locomotive used in New Zealand. The class were purchased from Mitsubishi Heavy Industries with a modernisation loan from the World Bank to replace steam locomotives in the South Island, where most of the class members worked most of their...
in 1968 brought about their ultimate demise. As they were displaced from duties in the late 1960s, some members were used on the Main South Line, including hauling the South Island Limited
South Island Limited
The South Island Limited was a passenger express train operated by the New Zealand Railways Department between 1949 and 1970. It operated between Christchurch and Invercargill via Dunedin, and in its heyday, it was New Zealand's premier express....
.
The first withdrawals were KBs 966 and 969 in October 1967; both were cut up for scrap. KB 969 was withdrawn after hauling the only ever double-headed
Double-heading
In railroad terminology, double-heading or double heading indicates the use of two locomotives at the front of a train, each operated individually by its own crew. The practice of triple-heading involves the use of three locomotives....
KB train, having suffered a cracked motion bracket. Before it was sent to the breakers' yard, it was incribed with a message reading "Goodbye Kb 969, you'll come back as roofing iron
Corrugated galvanised iron
Corrugated galvanised iron is a building material composed of sheets of hot-dip galvanised mild steel, cold-rolled to produce a linear corrugated pattern in them...
".
KB 967 was withdrawn in October 1968. This left only three KB's in service (965, 968 and 970), and of those, only 968 was serviceable; the remaining two were withdrawn by March 1969. 968 made its last journey on 22 June 1969, hauling a railway enthusiast's excursion from Christchurch to Arthur's Pass and return.
Preservation
NZR donated members of the K and KA classes for preservation, but due to the considerable technical similarities, it chose not to donate a KB. Instead, enthusiasts had to purchase one at the scrap market rate of NZ$1500 (equal to $22,200 in December 2008 dollars). KB 968 was supposed to be cut up the week following its last excursion, but a collection on the return journey was sufficient to temporarily save the locomotive. Retired school teacher Cyril Evans raised the rest of the $1500 by showing railway films to Christchurch school children and collecting their donations. The locomotive was then vested into the Ferrymead Trust on behalf of the children of Canterbury and was displayed for a number of decades at the Ferrymead RailwayFerrymead Railway
The Ferrymead Railway is a New Zealand heritage railway built upon the formation of New Zealand's first public railway, the line from Ferrymead to Christchurch, which opened in 1863. On the opening of the line to Lyttelton on 9 December 1867, the Ferrymead Railway became the Ferrymead Branch and...
. It is currently under restoration to main line operating condition at Mainline Steam
Mainline Steam
Mainline Steam is a New Zealand organisation devoted to the restoration and operation of historic New Zealand Railways mainline steam locomotives. Regular day excursions and multi-day tours are operated over rail lines throughout New Zealand...
's Christchurch depot.
List of locomotives
| Number | Builder | Introduced | Withdrawn | Notes |
|---|---|---|---|---|
| 965 | NZR Hillside | |||
| 966 | NZR Hillside | |||
| 967 | NZR Hillside | |||
| 968 | NZR Hillside | Preserved by Ferrymead Trust; leased to Mainline Steam Mainline Steam Mainline Steam is a New Zealand organisation devoted to the restoration and operation of historic New Zealand Railways mainline steam locomotives. Regular day excursions and multi-day tours are operated over rail lines throughout New Zealand... ; currently under restoration. |
||
| 969 | NZR Hillside | |||
| 970 | NZR Hillside |