EAR 59 class

The vehicles of Class 59 of the former East African Railways (EAR ) are steam type locomotives Garratt. They are considered the largest and heaviest ever built for an African railway locomotives and they are also the world's largest locomotives for narrow gauge.

History

The built early 20th century narrow gauge railway in the Kenya - Uganda Railway ( KUR ) from Mombasa in Kenya to Kampala in Uganda has a very challenging route profile. From sea level, the route rises to about 1,600 m above sea level to 2,743 m Nairobi, before heading back to about 1,150 m above sea level, situated on Lake Victoria, Kampala drops.

The two - and six-coupled tank engines first used could not move much more than their own weight on the highest slopes of the track so that Mallet locomotives procured with the wheel arrangement C'C for the steeps and 2'd - Tender locomotives for the flatter sections were.

Once the KUR had watched the successful use of Garratt locomotives from other railways, procured the railway in 1926 the first own Garratts ( class EC ). The drive was based on the 2'd locomotives, each still a barrel axis was added so that the first time a Garratt with the later very successful wheel arrangement ( 2'D1 ') ( 1'D2 ') was born. The locomotives proved themselves excellent, and the Railroad bought - apart from two series - in the episode only Garratt locomotives.

1948 emerged the East African Railways (EAR ) from the merger of KUR and the Tanganyika Railways. The EAR took over numerous Garratt locomotives, especially from the KUR, and introduced a new class system in which the Garratt locomotives were assigned to the classes from 50. The EAR continued the procurement policy of the KUR and was limited in new locomotives to the design of Garratt.

In the early 1950s reached the traffic volume between section Mombasa - Nairobi the limits of the existing locomotives and the section became the bottleneck for the import and export through the port of Mombasa. It was proposed to expand the route double track or to electrify, but this would have taken too long and caused too high a cost.

Studies and calculations showed that the existing track significantly larger than allowed locomotives at that time were in use. The then strongest Garratt - equipment ( Class 54) had an axle load of 14.2 t, the Einrahmenlokomotiven Class 28 reported 17.8 t on. The investigations showed, however, that the track would hold an average axle load of 20.3 tonnes. On this basis, a Garratt locomotive was ordered from Beyer Peacock, which surpassed even the built for the Russian broad gauge Garratt series Я of the Soviet State Railways in its mass and traction. Even before the delivery of the ordered nine aircraft in 1950, the order was increased to 34 pieces.

All locomotives were delivered in 1955 and designated as Class 59. They were the last steam locomotives procured by the EAR, because the class 60 had already been established prior to the delivery of the class 59. All 34 locomotives of Class 59 were named after the East African mountains, so the class was also known as "Mountain " class.

Technical Features

The class 59 has been called the wheel arrangement ( 2'D1 ') ( 1'D2 '), also called " Double Mountain ". This wheel arrangement have also the other major Garratt series. Few Garratts were built with the wheel arrangement ( 2'D2 ') ( 2'D2 '), but less in order to achieve high performance and to keep the axle loads within limits. A scheduled by the EAR as a class 61 design with this wheel, which would have 59 significantly exceeded in power and traction, the class, has not been more realized.

The boiler of the class 59 has a diameter of 2,286 mm - more than twice the track width and as much as the aforementioned Soviet Garratt. This resulted because of the narrow profile to some construction issues; However, on the whole, the locomotives referred to other Garratts made ​​by Beyer Peacock no special technical features.

The wheels were given as in the classes 57 and 58 have a diameter of 1.371 mm. The wheel flanges of the inner driving wheels were weakened to allow the passage through tighter curves ( with the previous designs, these wheels had no wheel flanges ). For the first time in a built locomotive for Africa were all axes and the rods roller bearings.

The locomotives were supplied with oil firing, however, are provided for the conversion to coal firing with mechanical grate feed ( Stoker ), in the event that changes the supply situation. The locomotives could carry 39 cubic meters of water and 12.27 cubic meters of oil.

As the class 57 ( class EC3 KUR ) and all subsequently for East Africa built Garratt locomotives was also the Class 59 prepared for a Umspurung on Cape gauge, since at this time to connect the East African meter gauge network with the Cape gauge network of the southern Africa was in sight. To this end, the wheels were slightly wider rims, so had to re-gauging only changed tires are shrunk and the position of the brake pads had to be adjusted. In addition, these locomotives were prepared for mounting the Janney coupling used in southern Africa, which is mounted higher than the coupling used in East Africa. At such Umspurung it is so far not come, even though the Cape gauge with the TAZARA has already reached Mombasa in 1976.

Instead of purchasing the above-mentioned class 61 a decision was made to increase the performance of locomotives available by installing Giesl ejectors. After initial trials in the years 1957 to 1959 all existing Garratt locomotives of the EAR were rebuilt in 1960, with the largest part of the class 59 in 1962 's turn. The performance of the modified machines were significantly higher, so that had to be distinguished in the schedules between converted and non- converted even locomotives.

Locomotives received

The locomotives of the class were still 59 to about 1980 in daily use. Two copies of class 59 are obtained. While the locomotive No. 5930 "Mount Shengena " only superficially repaired in Nairobi Railway Museum is, the No. 5918 "Mount Gelai " was brought in 2001 from the museum and restored to an operational state. It usually travels with tourist trains, but was already used as a substitute for fancy diesel locomotives.

The future of this locomotive is open. The privatization of the Kenya Railways in 2006 may temporarily interrupt the operation of steam trains; However, the feared complete cessation of passenger transport and thus the operation of steam special trains in favor of a pure freight is off the table.

The class 59 in comparison

Only one Garratt locomotive was even bigger and heavier than the class 59 - the already mentioned 1932 for the Soviet Railways ( SZD ) built single piece Я -01. But even these huge, built for the Russian broad gauge locomotive had - with the same wheel arrangement - a slightly lower axle load ( 20 tonnes instead of 20.3 t) and hence a lower tension than the Class 59 In addition, it was apparently not a success and is already have been dismantled in 1937.

The largest after class 59 Garratt are the eight in 1929 built Cape gauge machines of the South African Railways GL class, but had to make do with 19 t axle load. Slightly smaller, but heavier than the GL class, are the locomotives of classes 20 and 20A of the Rhodesian Railways (now National Railways of Zimbabwe ). With about 268 t the Australian Garratts the NSWGR class AD60 are even harder than the EAR class 59; their tension is, however, due to the relatively low axle load of about 16 tons under the said locomotives.

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