RR class 15 / 15A

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RR class 15 / 15A
ZR class 15 / 15A
NRZ class 15
Class 15 Garratt with serial number 417 in Thomson Junction, Zimbabwe, July 1990
Class 15 Garratt with serial number 417 in Thomson Junction, Zimbabwe, July 1990
Numbering: see text
Number: 74
Manufacturer: Beyer-Peacock
Year of construction (s): 1939-1952
Type : (2'C2 ') (2'C2') h4 (Garratt)
Gauge : 1067 mm ( cape track )
Service mass: 183.8 t
Friction mass: 78.2 t
Wheel set mass : 15 t
Driving wheel diameter: 1447 mm
Cylinder diameter: 444 mm
Piston stroke: 660 mm
Boiler overpressure: 12.65 bar (15A: 14 bar)
Grate area: 4.41 m²
Radiant heating surface: 19.7 m²
Tubular heating surface: 196 m²
Superheater area : 45.9 m²
Train brake: Suction air brake

The vehicles of classes 15 and 15A of the former Rhodesian Railways (RR) or the Zambia Railways (ZR) and the National Railways of Zimbabwe (NRZ) are articulated locomotives of the Garratt design .

74 built copies the locomotives after were class GMA / GMAM the SAR (120) the Garratt-type with the second largest number of pieces. Some of the locomotives are still in use today.

Development and delivery series

The locomotives have the wheel arrangement (2'C2 ') (2'C2'), also called "Double Hudson " or "Double Baltic". This wheel arrangement is well suited for higher speeds in both directions combined with a large water and fuel supply. But it was applied only to one other Garratt-type, the locomotives no. 250-259 of the Sudan Railways , which were as Class 17 and 15 years in the RR in action before they turn to the CFM were sold.

Class 15 was largely based on Class 16 - wheel arrangement (1'D1 ') (1'D1') - whose relatively good running characteristics, even at higher speeds, led to the desire for a locomotive with larger drive wheels that was also suitable for passenger trains on main lines . Initially, a (2'C1 ') (1'C2') with the same number of axles as the class 16 was planned, but inspired by the aforementioned Sudan Railways locomotives, it was decided to use an additional running axle in order to be able to carry larger supplies. The middle part of the locomotives with the boiler was largely identical to that of Class 16, the size of the drive wheels at 1447 mm corresponded to that of the Sudanese locomotives.

First, four Class 15 locomotives were purchased from Beyer-Peacock ; they were given the course numbers 271-274. For the first time - and in contrast to class 16 - these locomotives had a "streamlined" rounded front water tank, which later became a typical feature of modern Garratt locomotives. The rear bunker, however, retained the angular shape that had been common up until then.

The locomotives proved their worth and were particularly noticeable for their high availability; they achieved mileage of almost 10,000 km per month. The success led to the procurement of a further 70 locomotives of classes 15 and 15A, but only after the Second World War.

In 1947 10 locomotives with the numbers 275-280 and 290-293 were delivered, which differed from the first four by a modified, easier to manufacture shape of the front water tank. In addition, the rear water tank or coal box was now rounded off. Another 20 locomotives with a slightly different shape of the front water tank followed by 1948. In these, the coal supply had also been increased from 10 to 12.5 t. They were given the numbers 364–383.

The other deliveries between 1949 and 1952 with a total of 40 copies were designated as class 15A. Outwardly largely identical to the last series in Class 15, the main difference was the increase in the boiler pressure from 12.65 to 14 bar. The locomotives were given the numbers 384-423. The number 404 was later renumbered to 424; the reasons for this are hidden.

With the exception of the last 10 locomotives, which were delivered to Franco-Belge by 1952 as a subcontract for Beyer-Peacock, all 15 / 15A were from Beyer-Peacock himself.

With the introduction of classes 17 and 18, which were given the numbers 271-280 and 281-289, the early class 15 machines were renumbered. The first four were given the numbers 350–353 and the next ten numbers 354–363, so that class 15 / 15A now - with the exception of number 404 - occupied the number range between 350 and 424.

Over the years, the assignment of the individual locomotives to Class 15 or 15A has changed, as the boilers could be exchanged with each other and with those of Class 16A , which was a common practice in maintenance. It is no longer possible to deduce the boiler pressure from the locomotive number. The locomotives No. 352 and 353 from the first series as well as some locomotives of the second series received a front water tank that corresponds to the third series.

commitment

A Class 15 Garratt with a mixed train just before Dete (1990)

Class 15 main route was the international connection between Bulawayo via Francistown and Gaborone in Botswana to Mafikeng in South Africa . On this 775 km long route, the 15 / 15A practically had the traction monopoly, which means that the locomotives carried all types of trains. In the case of through-going trains, the locomotives stayed on the train without interruption, and a second locomotive crew drove along in a company car.

The locomotives, which can be used universally from shunting to passenger train service, were also used on the other main routes, from Bulawayo to Salisbury and Victoria Falls and on the route between Gwelo and Malvernia in Mozambique . A few were also used in Northern Rhodesia .

In 1964, Northern Rhodesia became independent. With the resulting division of the country into Zambia and Southern Rhodesia , however, most of the class 15 / 15A locomotives remained in the southern part.

reconstruction

Because of the rising oil prices after the oil crisis of 1978 , the NRZ decided in 1978 a reconstruction program for steam locomotives because they could be operated with cheaper domestic coal. 1980–1983 the still existing Garratt locomotives were completely overhauled and some points were modernized, including the installation of roller bearings . The task was entrusted to private companies, in particular to the RESSCO plants in Bulawayo.

Among the reconstructed locomotives were 34 from Class 15 / 15A, but none from the first two delivery series. Because the differences between classes 15 and 15A were already blurred by exchanging the boiler, the A was dropped completely and from then on all locomotives were designated as class 15. Because only a few locomotives remained in Zambia and therefore, unlike the class 16A and 20 / 20A, there were no major gaps in the numbering, the reconstructed class 15 locomotives kept their old numbers. In addition, they were given names of birds and other animals.

Because of the continued difficult economic situation in Zimbabwe, the reconstructed steam locomotives remained in service longer than originally planned. It was not until the turn of the millennium that the end of steam operation was decided, and the locomotives were only used for as long as the term of the boiler certificates allowed and as long as no major damage occurred. The parked locomotives then served as spare parts donors, but were not scrapped. Locomotives 386, 394 and 395 of class 15 were last in service.

Contrary to the plans, ten locomotives were or will be refurbished in 2006/2007, albeit not as thoroughly as in the early 1980s, so that further use is possible at least in shunting service and in front of suburban and special trains. Among them are four machines of class 15, No. 386, 395, 416 and 424. The processing of five more Garratts is at least under discussion; Class 15 No. 394 would be included.

Hwange coal railway

Two class 15 locomotives were taken over by the coal railway Hwange (formerly Wankie) from the NRZ and used for shunting tasks as well as the transfer to the NRZ station Thomson Junction . They were given the numbers 11 and 12 (formerly NRZ numbers 423 and 370). Because of the poor availability of diesel, one of these locomotives is still in service today, while the other is kept in reserve.

Museum locomotives

At least four class 15 / 15A locomotives are currently museum or monument locomotives, including two of the first four from 1939:

  • No. 350 (formerly No. 271) is in Kadoma along with two other locomotives .
  • No. 352 (formerly No. 273) has been in the Francistown train station in Botswana since 1976 .
  • No. 389 was transferred to New Zealand in 2011, where it is to be processed for use in front of tourist trains.
  • No. 401 is in the Livingstone Railway Museum in Zambia (see web link).

There are currently none of these locomotives in the Railway Museum in Bulawayo .

literature

Individual evidence

  1. ^ Report on the State of the Railways in Zimbabwe
  2. ^ Report on Hwange Colliery Co. Ltd.
  3. ↑ Class 15A Garratt Number 398

Web links