another photo

Discussion in 'Narrow Gauge Model Railroading' started by nachoman, Feb 17, 2007.

  1. nachoman

    nachoman Guest

    here is another photo from my layout. I switched it to black and white because the lighting in the layout room is poor and makes everything look yellow.

    kevin

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  2. Glen Haasdyk

    Glen Haasdyk Active Member

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    Nice picture, it that an MDC engine? I've got an outside frame that I'll get to run eventually.
  3. CNWman

    CNWman CNW Fan

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    I like it!

    Nice photo! I love how you got the engine going 'round a curve there!:thumb: However, the imediate area around the train looks kinds bare. You need some people or trees or something. Is this on the edge of a layout or something?
  4. Canopus

    Canopus Member

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    Well it's outside frame, which means that you score bonus points as far as I'm concerned. You see, I hate inside frame with a passion, LOL. :D

    I take it that this is HOn3?
  5. nachoman

    nachoman Guest

    yeah, it's a roundhouse outside frame. I've got an inside frame as well, but needs to be put back together. And yeah, it's the edge of the laout so behind the train is blank wall
  6. nachoman

    nachoman Guest

    here is a photo of the whole layout for reference.

    kevin

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  7. Canopus

    Canopus Member

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    So it's a work in progress then. Good, keep us updated!

    And if I were you, I'd leave that inside frame engine in pieces. :D
  8. steamhead

    steamhead Active Member

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    It's amazing what can be done in small spaces...!!! Good job...! !:thumb:
    Now, can someone 'splain this business with the "outside" frame?? :confused:
  9. Mountain Man

    Mountain Man Active Member

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    According to a rather angry and pointed commentary by one of the oldtimers on this forum, w are no longer supposed to ask questions if the answers are either available by searching this forum, or from Google. :rolleyes:

    Personally, I have seen this comment numerous times in otherwise decent reference books, and I have no idea what the difference is, either. Neither does Google, which does give me links to other frames, such as picture frames, but thats Google for you - the lowest common denominator search engine.
  10. Mountain Man

    Mountain Man Active Member

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    According to an angry and pointed remark by one of the forum oldtimers, we are not supposed to ask questions any longer until we have exhaused all possible alternative avenues. :rolleyes:

    OTH, I read any number of books that use this term and I have no idea what it means either, and neither does Google.
  11. Canopus

    Canopus Member

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    [​IMG]

    This locomotive is outside frame. Note that the connecting rods are connected to CRANKS rather than directly to the wheels themselves. Between the cranks and the wheels is the chassis frame. The frame is the part that sits on the axles, and is often where all the suspension is.

    [​IMG]

    This locomotive from our friend at the Pacific Coast Air Line is inside frame. Note how there are no cranks, and that the frame is between the wheels, rather than the wheels being between the frames. On these locomotives, the connecting rods are connected directly to the wheels.
  12. sumpter250

    sumpter250 multiscale modelbuilder

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    Aside from the aesthetics, there is a sound reason for outside frame usage. It is more stable.
    While the stability of narrow gauge equipment is inherently questionable ( the narrower the base, the less stable the object, with respect to rolling over), using an outside frame does widen the base, with respect to the center of gravity, and decreases the tendancy of the equipment to roll/tip over.
    That said, narrow gauge right of ways need to be just a bit wider, where outside frame locos are used. On a 3' gauge, cylinder centers are typically 6' for an inside frame loco, and 8'-6" for an outside frame loco. The MDC locos conform to the typical cylinder spacing
    (8'-6" is not untypical for a standard gauge loco). I have an inside frame 2-8-2, and two inside frame 2-6-6-2s, but I have to admit, my preference is outside frame.
  13. Canopus

    Canopus Member

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    I think what you mean is that outside frame produces a lower center of gravity, by giving additional weight lower down. This is more of a traction advantage rather than one of stability. It doesn't widen the base in an effective sense, because the wheels are still the same distance apart. The stability difference between O/F and I/F locomotives here is pretty negligable. In this sense, an inside frame locomotive is actually more stable because it's usually narrower. Outside frame however allows you to accomodate a larger boiler and larger cylinders, thus increasing the weight and therefore adhesion.

    The thing with trains is that the physics aren't what the lay man usually expects. The instability of narrow gauge is more of a myth than a fact - people who believe this usually don't take into account that trains use weight to keep them pinned to the rails (adhesion, as I mentioned earlier). This is as opposed to (automobile) cars (with which people often have them confused), which use center of gravity to keep them from rolling over when cornering. So long as the weight above the wheels is greater than the weight either side of them, then it's stable, so long as it doesn't do anything crazy. The only reason a narrow gauge locomotive would roll is if it attempted a very sharp turn at high speed, and the weight shifted (water in the boiler, plus coal in tender). Generally when a locomotive attacks a corner when it's moving too fast, it will just either break the tracks and carry on going forward, or will jump off them and carry on going forward. Usually after doing that it will roll, because in most cases it had already started cornering by the time it had started putting excess stress on/started leaving the track.

    The only other circumstance in which I've seen a narrow gauge locomotive roll onto it's side was due to poorly laid track, which is/was the most major failing of narrow gauge railroads worldwide. This is usually the result of underfunded permanent way departments, which is caused by the mentality among operators that narrow gauge produces significant savings in PW construction and maintenance costs, and therefore funding to that department can be cut without consequence.

    The most important thing to remember, is that in terms of balance, the working surface is the part of the locomotive that is in contact with the ground. Making it wider or narrower doesn't change the fact that the wheels are only 2 to 3 foot apart. It does however mean that when it starts to tilt, it's more likely to roll in that direction. However, contrary to popular belief, it's not as easy to get a NG locomotive to tip as people might think. For a start, the suspension is trying to stop you from doing just that, and also the sheer weight of the thing would prefer it to be bolt upright at all times. Since it's more fuel effficient to drive like your grandmother, there's no need to worry about tilt during high speed cornering.

    I'm sure you knew all this already, but I felt like stretching my brain a bit. :thumb: Also some of this may be of interest to people browsing the forum in general.
  14. nachoman

    nachoman Guest

    i think whether IF or OF may also come down to railroad preference. All of the large D&RGW 2-8-2s were outside frame. East Broad top's 2-8-2s were all inside frame. Sumpter valley had mostly inside frame as well as White Pass. Colorado and southern and Rio Grande southern were mostly inside frame locos, but those railroads really don't count because they did not puchase any new locomotives after 1900 (Outside frame locos were first made about 1900). And the largest U.S. 3' gauge locomotives, the Uintah 2-6-6-2ts were inside frame.

    kevin
  15. Canopus

    Canopus Member

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    Not so, the outside frame design has been around since well before 1900.
  16. sumpter250

    sumpter250 multiscale modelbuilder

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    Now that, I didn't know. What locomotive, and for which railroad, was the first outside frame delivered?
  17. nachoman

    nachoman Guest

    The crystal river railroad had some built in 1900 and 1903. the Morenci Southern in arizona in 1903. Those are the earliest I know of.

    kevin
  18. Canopus

    Canopus Member

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    I'm not sure exactly, but I know that it's old. The oldest that I know of is Pentewan, a Manning Wardle 0-6-0 tender locomotive, which was built in 1873. I know that by then it was a pretty standard design for narrow gauge locomotives in the UK. Trevithick's Penydarren, one of the first locomotives ever built, was built in 1803. So I'd say that they probably first came into common use in the late 1850s.
  19. sumpter250

    sumpter250 multiscale modelbuilder

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    pentewan 2'-6"gauge 0-6-0 that ran on the 4 mile Pentewan railway. They also had a Manning Wardle 0-6-2 st Canopus. Perhaps the origin of your screen name?
  20. Canopus

    Canopus Member

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    Yes it is! I was wondering when someone would spot that. :thumb: The trackbed of the old Pentewan railway runs past the end of my back yard, about 10 meters from my house.