NZR Bb class
Encyclopedia
The BB class of steam locomotives comprised 30 engines operated by New Zealand Railways
in the North Island
of New Zealand
. Similar in design and appearance to the preceding B
and BA
classes, the first BB class locomotive entered service in February 1915, with the last to commence operations doing so on 8 March 1917. All were built by A & G Price
Ltd of Thames, New Zealand
, and as their cylinders had a larger diameter than the B and BA locomotives they were capable of generating more power to haul heavier trains. The BB class could haul up to 700 tons of freight on a level railway line, though they were limited to a top speed of around 40 mph.
The BB class did not solely haul freight trains. They were also utilised to haul passenger trains, generally on branch line
s where light track meant trains could not be operated at speeds unattainable for the BB class. These trains included services for miners working in coal mines along branches in the Waikato
region.
In the later days of steam, powerful locomotives such as the K class
were hauling heavy trains that the C class
and other shunting locomotives at yards and depots simply could not handle. Accordingly, ten members of the BB class were modified to perform shunting duties and they successfully took on the heaviest of roles.
Most BB locomotives survived into the 1960s. During that decade, the complete withdrawal of the class was undertaken progressively, with the last two, BB 626 and BB 633, formally removed from service in August 1968. Another one of the last to be withdrawn was BB 144 in October 1967, and it survived to be preserved by Mainline Steam
, though it is presently inoperable. No other BB locomotive has been preserved.
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...
in the North Island
North 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...
of 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...
. Similar in design and appearance to the preceding B
NZR B class (1899)
The B class of 1899 was a class of steam locomotives that operated on New Zealand's national rail network. An earlier B class of Double Fairlies had entered service in 1874, but as they had departed from the ownership of the New Zealand Railways by the end of 1896, the B classification was free...
and BA
NZR Ba class
The BA class was a class of steam locomotive built by the New Zealand Railways Department for use on New Zealand's national rail network. The first BA entered service in November 1911, with the last of the 11 class members introduced on 14 May 1913....
classes, the first BB class locomotive entered service in February 1915, with the last to commence operations doing so on 8 March 1917. All were built by A & G Price
A & G Price
A & G Price Limited is an engineering firm and locomotive manufacturer in Thames, New Zealand, established in 1868. In 2004 a precision formed yacht keel division was formed to make the Maximus canting keel...
Ltd of Thames, New Zealand
Thames, New Zealand
Thames is a town at the southwestern end of the Coromandel Peninsula in New Zealand's North Island. It is located on the Firth of Thames close to the mouth of the Waihou River. The town is the seat of the Thames-Coromandel District Council....
, and as their cylinders had a larger diameter than the B and BA locomotives they were capable of generating more power to haul heavier trains. The BB class could haul up to 700 tons of freight on a level railway line, though they were limited to a top speed of around 40 mph.
The BB class did not solely haul freight trains. They were also utilised to haul passenger trains, generally on branch line
Branch line
A branch line is a secondary railway line which branches off a more important through route, usually a main line. A very short branch line may be called a spur line...
s where light track meant trains could not be operated at speeds unattainable for the BB class. These trains included services for miners working in coal mines along branches in the Waikato
Waikato
The Waikato Region is a local government region of the upper North Island of New Zealand. It covers the Waikato, Hauraki, Coromandel Peninsula, the northern King Country, much of the Taupo District, and parts of Rotorua District...
region.
In the later days of steam, powerful locomotives such as 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...
were hauling heavy trains that the C class
NZR C class (1930)
The C class consisted of twenty-four steam locomotives built to perform shunting duties on New Zealand's national rail network. It is sometimes known as the big C class to differentiate it from the C class of 1873.-History and construction:...
and other shunting locomotives at yards and depots simply could not handle. Accordingly, ten members of the BB class were modified to perform shunting duties and they successfully took on the heaviest of roles.
Most BB locomotives survived into the 1960s. During that decade, the complete withdrawal of the class was undertaken progressively, with the last two, BB 626 and BB 633, formally removed from service in August 1968. Another one of the last to be withdrawn was BB 144 in October 1967, and it survived to be preserved by 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...
, though it is presently inoperable. No other BB locomotive has been preserved.