bridge /tunnel???

Discussion in 'N / Z Scale Model Trains' started by belg, Oct 28, 2003.

  1. belg

    belg Member

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    Guys and ladies I'm having some trouble trying to get some thing in this area that will look real. I'm posting some pictures of the area in question, the overpass is 5 1/2" above the lower level and crosses three tracks below. Any questions you have that will help me come up with a reasonable crossover I will gladly try to answer. N scale to boot.

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  2. belg

    belg Member

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    over head view

    #2

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  3. Catt

    Catt Guest

    :confused: Whats the problem? Looks to me like your off to a great start.Since you have all this girderbridge going I think you should support it on steel trestle bents in stead of concrete.
  4. belg

    belg Member

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    the problem is that there is no space under the girder for the steel trestles. Unless they were spaced so far apart that it would not look right.
  5. Matthyro

    Matthyro Will always be re-membered

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    If you can't have supports from below how about a Warren Truss bridge as it will support quite a long span.
    Something along the lies of this one which serves as the duckunder into my layout area.

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  6. belg

    belg Member

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    Robin I like the bridge but as you can see in the second picture this is on a curve and I don't think a bridge like that would be structurally sound in that configuration.(Would it)
  7. Matthyro

    Matthyro Will always be re-membered

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    A lot of bridges that go around a curve are built in small straight sections so I am sure you could do a Warren truss that way. The inside of the curve would be slightly shorter than the outside . There is probably a prototype around somewhere.
  8. ezdays

    ezdays Out AZ way

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    Robin,

    How long (actual) and how high off the floor is that bridge?

    Oh, and what's it made from? And please don't tell me cereal box cardboard..:) :)

    Don
  9. Matthyro

    Matthyro Will always be re-membered

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    Don, the bridge is 32 inches long and is 57inches above the floor.
    It is made out of a mix of corrugated cardboard and cereal board and turned out to be amazingly strong.
    That's why I suggested something similar for Belg
  10. jland31

    jland31 Member

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    WARREN TRUSS BRIDGE

    I have an application for a Warren Truss Bridge that would be placed on a decline.

    Is it permissible [prototypical] for one end of the bridge to be lower than the other?
  11. ezdays

    ezdays Out AZ way

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    Robin,

    Thanks, it should be strong since that's the way trusses are, regardless of the material used, apparently...

    That is a very comfortable hight for a duckunder. I've seen them 40" off the ground and kinda risky for both the span and the person.:eek: :eek: :rolleyes: :rolleyes:

    Don
  12. kettlestack

    kettlestack Member

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    Belg, I'd agree with Catt and Robin. There's a couple of reasons for leaving it as a bridge....
    1) .. The upper track is too low to warrant a tunnel, in real the engineers would make a cut rather than a tunnel.
    2) .. Access to the switches is easier, you never know when you're going to need space for your hands to get at them :) .
    3) .. Like Robin said, there's probably a prototype somewhere.

    Errol
  13. CN1

    CN1 Active Member

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    I see no problems with your bridge.

    Sometimes the support would be placed further apart than they need to. To compensate you can make them stronger since they have more load to support and we can imagine that the "floor" of the bridge is stronger also and therefore heavier, wich in turn would required stronger supports.

    Wow! did I just repeat myself on this one?
  14. CN1

    CN1 Active Member

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    real life example:

    [​IMG]
  15. CN1

    CN1 Active Member

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    pictures are from japan.

    [​IMG]
  16. CN1

    CN1 Active Member

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  17. MCL_RDG

    MCL_RDG Member

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    A lot of...

    ...tree tops. Alot, a real lot.

    Mark
  18. belg

    belg Member

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    Thanks for all the ideas guys I will probably use a combination of a couple of the ideas. Will post progress as it's made and draw a sketch to show you what it's going to be.

    TREETOPS ?????????????


    CN 1 Your link was extremely helpful thank you.
  19. CN1

    CN1 Active Member

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    You're welcome.

    Your question was a good one too:D