Bridge question?

[trainsteve2435]

Hello everyone, im planning a bridge on my layout, but i have a problem. Im not much of a carpenter, so i thought i could get some help here. My benchwork is already complete, its open grid construction. I used 1" x 4"'s to frame it up and topped it with 1/2" plywood and then added 1" extruded foam on that. I need to add the bridge below to my layout, but im not sure how to box it in or even how to do it. The bridge is sitting where i want to install it, and i have already removed the 1" x 4"'s from underneath the layout, so now all thats left is the plywood. Can someone point me to a place with some information or give me some suggestions on how to do this the right way? Thanks in advance!
steve

 

[COMBAT]

Do you want to make the area the bridge crosses over deeper the that?

 

[trainsteve2435]

Yes, i want it to give the illusion of crossing a big shallow river. I was thinking of around 10" to 12" deep, what do you think?

 

[billgee-n-scale]

You need to remove some of the plywood under the bridge. Create a cavity as deeo as you like (the deeper the better) using foam board.

 

[MilesWestern]

10" to a foot deep would be a 60-85 foot drop in HO!! a lazy shallow river would warrant 3"-4" at the MOST, espically with the width of that bridge. Although in switzerland, colorado, and venezuela, this can be disproven. However, judging by the surrounding relatively flat pink expanse on either side, how about three or four inches?

 

[LongIslandTom]

Back in 1988, I read Bob Boudreau's article in Model Railroader on how he did that... He cut the plywood with a saw in the shape of the river/stream/pond, but the sawing was done at an angle to serve two purposes: 1) the angled cut serves to simulate the slope down to the riverbanks, and 2) the piece that is cut out is then glued to the bottom of the benchwork to form the depressed river bed.

Pretty neat. The result can be seen at Bob Boudreau's Fundy Northern website:

Looks like a promising approach.. I'm going to try that technique with my own layout eventually. :thumb:

 

[COMBAT]

The size and depth is completely up to you. The issue is you didnt build the table to accomadate the ditch....

With that in mind you can do a couple of things.

Since you want 10" to 12" inchs of depth you now are going to have to remove the plywood. Get a saw and cut it out. You are also going to have to change the way your bench is constructed here. You can do it a lot of different ways. If you only want to show a whole in the ground then thats up to you. To cut then bench make sure it is braced and then cur out the section you want to remove. I was going to show you a picture of this, but the website it is on is down right now. I will give you the link to take a look later when it comes back up. http://www.free-mo.org/ If you keep hitting the refresh button on your browser you will see a bunch more photos. Do it A LOT!

I hope that helps, for now:thumb:

 

[zedob]

Or, you could always leave it like it is, put a rock cliff behind it and presto...
CSX'x line just south of Westpoint Academy.:thumb:

I think there is a prototype for every "un-prototypical" scene that MRRers can come up with.

 

[TruckLover]

It would be cool to see a valley under the bridge but I am liking that idea of just leaving it after seeing that sweet picture of the CSX line.

Up to you, what ever you want to do.:thumb: :thumb:

 

[Jim Krause]

I did much the same thing that you are asking about. I removed a portion of the benchwork and boxed in the opening with 1X4 structural members. then added a piece of 1/2 inch plywood for a base. I then built up the contours with scrap foam, installed bridge abutments and a Walthers double track bridge. Look before cutting. There may be wires underneath.

 

[Tim H]

Here is how I am going to build the ravine in my layout. I want to use the Micro Engineering 150' Steel Viaduct Bridge. My layout isn't huge, so there isn't a whole lot of room to build the track elevation very high. So my alternative is to make the bench work lower. I am going to use a combination of 1x4s and 2x8s to step the bench work down almost 12 inches. It will actually be more than 12 inches after all the foam is added. I sketched in the ravine to show graphically what I was planning on doing with the groundwork.


Click the thumbnail for a larger image.

 

[COMBAT]

I will want pictures of this as you progress you know!

 

[Nazgul]

LongIslandTom....that's some great info there (solves two probs at once)
zedob.......great pic!