Weird steam locomotive

Discussion in 'Getting Started' started by Collyn, Feb 10, 2007.

  1. Collyn

    Collyn Member

    I caught apart of this show featuring all sorts of trains. One that caught my eye was this train that takes turists to and across victoria falls. The track is extreamly lite weight so the loco has to have more wheels to spread out the weight. These pics were captured from the video so they are not very good.

    Attached Files:

  2. nachoman

    nachoman Guest


    a beyer-garatt (sp?)
    unusual indeed!

  3. artur_p

    artur_p New Member

    it looks like the 4-8-2+2-8-4 Garratt from South Africa.
  4. Triplex

    Triplex Active Member

    Garratts were quite common in many African countries and also found in Australia and even the UK. In general, it seems that railroads that emulated British practice in the steam era used Garratts when they needed articulateds, while railroads that emulated US practice used Mallets.
  5. nkp174

    nkp174 Active Member

    Actually, it was very common here in the US to spread out the weight of a locomotive to reduce the axle loadings.

    Take for instance a C&O 2-6-6-6, they actually out weighed the UP 4-8-8-4s, yet had 2 fewer axles. The result was the heaviest axle loadings of any locomotive ever built...and the ultimate machine for wearing out track. (That coupled with the penalty from grossly exceeding the total weight (a danger with bridges), the Lima Locomotive Works cheated in the scale house and lied about the total weight to avoid trouble with the C&O. It was eventually discovered when the Virginian ordered their "light" alleghanies that were quoted at a higher weight the C&O alleghanies...and the ensuing settlement with the C&O caused Lima to lose money on the 2-6-6-6 design.)

    An excellent example of utilizing lighter axle loadings was what occured north of the border. The Canadian National, which was similar to our Conrail, utilitzed 4-8-4s to reduce the axle loadings on it's sub-par track while the well built Canadian Pacific utilized 4-6-4s.

    Btw, the Beyer-Garrat pictured would be a meter gauge locomotive. They also have berkshires & such. If I recall, part of the design was to keep some of the weight from the water on the drivers, but the downside is that if you need to start a train without much water, you have a lower factor of adhesion.

    Note: a Factor of Adhesion is the ration of the weight on drivers to the tractive effort. 4.0 was considered ideal. A locomotive with a low FoA will slip alot...especially when starting a train. The N&W class A's actually had their tractive effort reduced (limited cutoff) in order to help improve their factor of adhesion. It doesn't matter how powerful a locomotive is if it slips to much to start a train.

    EDIT: the well known large US steam engines...Big Boys, Challengers, Yellowstones, Alleghanies, N&W Class As, and such were NOT mallets. A mallet recycles steam while these super power locomotives generated enough steam to not need recycled steam.
  6. Dragon

    Dragon Member

    <quote>the well known large US steam engines...Big Boys, Challengers, Yellowstones, Alleghanies, N&W Class As, and such were NOT mallets. A mallet recycles steam while these super power locomotives generated enough steam to not need recycled steam.</quote>

    Wasn't the definition of a Mallet one that takes the exhaust steam from the high-pressure cylinders and puts it through a set of low-pressure cylinders?
    No matter HOW MUCH steam these big locos generated, don't they still take the exhaust from the rear cylinders and put it through the front set?
  7. bigsteel

    bigsteel Call me Mr.Tinkertrain

    i thought all articulateds used the leftover steam from the rear cylinders to power the front cylinders.i have a book on it ill look it up later.
  8. Triplex

    Triplex Active Member

    What was very common? Mallets (well, actually, most of them weren't "true" Mallets) were the preferred type of articulated in North America. There were no Garratts here.
    South African railways are 3'6" gauge.
  9. slekjr

    slekjr Member

    I was under the impression that Mallet designed the hinged locomotive and that we had both simple and compound types here in the US. The compound being the ones that reused the steam in the front drivers, hence needing larger pistons.
  10. Omber

    Omber New Member

    Garrats were extreemly popular in Africa and to some extent in Australia I believe due to the massive power they produced on relativley light axle load (remember that most of African and Australian lines are to these days 3ft 6in lines not standard gauge running modern trains at high speeds of 80kph and units developing horsepower that is similar or same to that seen on standard gauge RR's in North America.
  11. Triplex

    Triplex Active Member

    Not all African countries use 3'6". Many use metre or standard. According to Australia has over 17000 km standard, 16000 km 3'6", 7000 km 5'3" and 4000 km 2'. New Zealand, whereas, is mostly if not all 3'6".
  12. Jim Krause

    Jim Krause Active Member

    slekjr is correct in his comment about mallets, simple and compound. There is a video available about a Beyer Garrett that was bought in South Africa and returned to Great Britian for use on a tourist railroad.
  13. Omber

    Omber New Member

    Sorry :) I didnt know the detailes but I did read about Garrants being the preveil type in Africa and Oceania, so I just wrote what I read :) While on the topic - has anyone ever seen any model Garrats for H0 scale ?:)
  14. Jim Krause

    Jim Krause Active Member

    There is a company in Great Britian called Backwoods Minatures that either has or will have a narrow gauge Bayer Garrett available.

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