NPBH - Tieing together CV trestles.

badlandnp Apr 20, 2017 at 1:39 PM

  1. badlandnp

    badlandnp TrainBoard Supporter

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    So, am needing to stitch together 4 Central Valley 150' through girder bridges with a Micro Engineering girder on each end of the run. The delicate details of these Truss bridges seems to preclude a permanent stiffener underneath. Any ideas on tieing these together so the track ends up flat? The total run will be about 53 inches of bridge with the two 4.5 inch girders applied to either end. I took one kit out last nite and started cleaning up the parts and eyeballing the assembly and am puzzling it out, but could sure use an idea or two, or three, or.....?
     
  2. SP-Wolf

    SP-Wolf TrainBoard Member

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    When you say "stitch" together - are you going to build them into one continuous through bridge (This would be one crazy bridge) -- or are you going to butt them together? If you are going to butt them together - wouldn't the piers at each bridge joint keep them straight - ?

    Kind of like this: This is about 2 feet

    [​IMG]

    Thanks,
    Wolf
     
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  3. bman

    bman TrainBoard Member

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    While I've built bridges from both of those mfg's, I've not combined them with each other. I guess it would really depend on how you are supporting the span. Are you using stone/concrete or steel bents. I would do a google search on railroad bridges and see how it is done in 1:1. You'll be basically doing it the same way. You will have to use different footings for each individual span to level the bridge decks with each other. if you click the link and look at the photo of the 14th St bridge over the Ohio River in Louisville, you can see where the girders are embedded into the masonry pier while the truss span is on footings on top of the pier. Or this Louisville and Indiana RR bridge on the second photo link.

    https://en.wikipedia.org/wiki/Fourteenth_Street_Bridge_(Ohio_River)
    http://www.wikiwand.com/en/Louisville_and_Indiana_Railroad

    Hope this gives you an idea on how to start.
    And of course while I was typing SP-Wolf's bridge is a good example of doing this changing the pier height to level the bridge decks. Nice work there.
     
  4. badlandnp

    badlandnp TrainBoard Supporter

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    There will be piers between the spans. However, I would like to have the track be as flat as possible with as few joints as possible. This will end up a very long bridge crossing the Yellowstone River. The CV tie plates are ready for rails to be attached, but I really don't want to have all those joints between the spans.
     
  5. acptulsa

    acptulsa TrainBoard Member

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    Flex track rails are 30" sections. Would that not work?
     
  6. Point353

    Point353 TrainBoard Member

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    Is it too late to consider using Micro-Engineering bridge flex-track in place of the tie sections that came with the kit plus separate rails?
     
  7. badlandnp

    badlandnp TrainBoard Supporter

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    Was looking at doing the flex track deal, also. However, the ties are a bit shorter and I suppose I should put up a couple more pics of the kit, this evening.
    Here's the prototype inspiration. I will have to come up with piers to match NP's practice.
    PIC_0309 (1).JPG PIC_0308 (1).JPG PIC_0896.JPG
     
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  8. bman

    bman TrainBoard Member

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    You could remove the ties from any brand of flex track and slide that rail onto the CV bridge decks. Your going to have at least one joint since flex is 30" long and your bridge is around 53". You could slide 2 of the CV decks onto one end of a piece of flex(whatever brand/type you choose) and leave the ties on the rest of that flex for use on the ME bridge section and make the joint in the middle of the bridge over the center pier. Alternatively, CV sells the bridge tie and stringer parts separately. You could use these on top of the ME girder bridge and just use whatever rail you choose to use. This way your track on the entire bridge will be the same style. Just slide the rail through the CV decks. You'd still have a joint somewhere though. But only two sections of track with the tie sections installed just waiting to be placed onto the completed bridges. When I built the CV kit, I installed the rail and deck last after everything else was completed. I can't remember what the kit instructions say. But sliding rail onto the deck of a completed bridge didn't sound like my idea of fun.
     
    Last edited: Apr 21, 2017 at 1:31 PM
  9. SP-Wolf

    SP-Wolf TrainBoard Member

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    OK, this is what I did: I used Micro Engineering flex track - I removed the ties that went onto the through bridges. So, I have one continuous piece of rail for the entire length of my bridge. Yours would be a bit different as you have such a long span in between the ME bridges on the ends. Would be a huge waste. This may take some work - Perhaps you could use Atlas C55 flex -- 2 pieces. Start at the Ends - remove enough of the ties "spacers" to create the bridge spacing of the ties - then remove the rest of the ties that would go through the through bridges -- you should only have one rail joint.

    Just a thought,
    Wolf
     
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  10. mtntrainman

    mtntrainman TrainBoard Supporter

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    Offset the flextrack joints if you use just the rail ....

    __________ ____________
    ___ ________________ ___

    Make sure the rails go past the bridge gaps and you should end up with good solid track over those gaps...JMO
     
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  11. nscalestation

    nscalestation TrainBoard Supporter

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    I have put together 3 of these kits so far but for my prototype I needed to shorten them to 3 sections from the stock 4 sections plus the ends. I have found that when assembled these get nice and strudy. Build on a nice flat surface so the bottom stays square.

    So it looks like your through truss bridges are 6 sections in length plus the ends. You will need to use 2 kits for each of your bridges. Offset the splices by at least 1 section and on the frame use the included riveted gussets to reinforce the joints and hide the seams in the outer exposed surfaces of the beams. It may also be good to reinforce the inward facing surfaces with some thin styrene strip. For the large girders that the track rest on for sure reinforce on the inside as that won't show at all.

    On the one bridge that I have installed so far on the layout I removed enough of the center ties from a M/E section of flex track to snap in the CV bridge ties that come with the kit. I have some photos of this in this on my layout blog.

    http://palisadecanyonrr.blogspot.com/2017/02/finishing-thru-truss-bridge-at-gloconda.html

    Interesting project, keep us posted as to how it progresses.
     
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  12. badlandnp

    badlandnp TrainBoard Supporter

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    Thanks for the input. So, it loooks like a weekend of watching trains go round and building bridges.
     
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