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I Need Some Help on This Bridge!

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  • Member since
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I Need Some Help on This Bridge!
Posted by Trainzman2435 on Friday, February 21, 2020 1:04 PM

Guys, i am at the point where i need to come up with some ideas on how to install the bridge below. My benchwork is open grid with 1/2" plywood top and covered with 2" foam. As you can see by the picture the bridge is a bit too tall even after i remove the 2" of foam. I really need some suggestions and ideas on how to make this a pleasing scene. Below the bridge i want to add a river and make it appear as if it meanders back under the bridge and opens up wider as it goes and eventually disappears. I would really appreciate any help or ideas and suggestions, even pictures lol. The foam riser is 4" tall and as i said, there is an additional 2" of foam board that i know will have to be cut out, i just need to figure out how to do it in order to look nice. Also, if anyone has any ideas on how i could model cement blocks for the bridge peer feet to set on would be great....Thanks everyone!

 

P.S....The black line you see behind the bridge right in front of the other foam risers is where the scenic divider will be installed!

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Posted by Track fiddler on Friday, February 21, 2020 1:55 PM

I would consider cutting the lower sections of your 2 pier truss supports off with a razor saw, giving you more room to work with.  This may give you a little more room left to carve the river in your foam if you have room to leave some.

Since foam is so easy to work with,  I would mark out the squares where your pier truss supports set.  Then you can leave some of the square shaped forms to create your cement supports.  I always use Fast & Final when I'm finalizing foam structures before I paint.  It works so well with foam.

Some foam structures with a ballpoint pen used and Fast & Final where needed, before paint. 

This basically free technique works excellent for abutments and stone retaining walls as well.

 

That's the way I'd tackle it.  There's always more than one way to do things thoughSmile, Wink & Grin

 

 

TF

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Posted by mbinsewi on Friday, February 21, 2020 3:06 PM

I guess you chalk that up to an "OOOPS" in the overall planning. But this will work.

The only thing you can do, with out changing the bench work, is cut out foam, and set the supports on the plywood, after cutting the supports to right length, as TF says.

Make the river bottom right on the plywood, and use your choice of landscape techniques to "slope" the banks up a little, to the sides of the ravine.   The concrete piers, needed to support each leg of the trestle supports (bents, I believe is the term) , should show just above the landscaping.

When deciding what the over all height the supports needs to be, take into consideration the height of the support foundations needed under each leg.

Mike.

 

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Posted by doctorwayne on Friday, February 21, 2020 4:47 PM

This is sorta the same as your bridge, but I used Atlas deck-truss bridges between the piers to gain some length...

The footings for the towers were made by stacking .060" sheet styrene, then filing each to a pyramid-shape.  Since the plaster-on-screen landforms were already in place, the bottoms of the footings needed to be carved to at least roughly match the terrain.

 

This one is over what will eventually be a river, with similar styrene footings, while the piers for the bridge in the foreground were made with Durabond patching plaster, cast in homemade styrene moulds...

 

The terrain will all be covered in trees, and as you can see, the source of the river is hidden behind the hill to the left.

This is a different style of bridge, using both Micro Engineering and Atlas components...

...and with the "water" in place....

The reason I've included it is to show that its origin is also unknown (all rivers on my layout flow towards the aisles), so there's a beginning and end to each, but neither is shown - one hidden, the other somewhere in the aisle beyond the layout's edge.

When viewed from above, the river simply comes from somewhere in the forest...

(Photo courtesy of Secord Air Services)


All of the bridges are removeable, as there are styrene plates on the bottom of each support leg, with a hole drilled in each.  The holes fit over 3/32" piano wire protruding out of each of the footings, ensuring perfect and stable alignment.

The first one finally got some scenery around it...

As others have mentioned, I'd create the contours for the river's banks, then shorten the support towers as needed, so that the bridge will fit into the scene.

Wayne

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Posted by Trainzman2435 on Saturday, February 22, 2020 10:13 AM

Guys, thanks for the ideas and suggestions, i appreciate them. Wayne, your layout and the bridge scenes look great sir, i only wish i had a drop of your skill. On your tall steel viaduct picture, about what are the sizes of the pyramid shaped concrete pillars you made there? They look awesome and are about what i am looking for....Thank you very much!

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Posted by selector on Saturday, February 22, 2020 12:30 PM

I make the bridge to 'sort of' fit my vision for that location, but the key is to place it, and to support it, AT GRADE.  There should be no dip or rise at either end because, especially along a curve, you'll have derailments there...guaranteed.

So, I place the bridge, and mock up supports and clamps, if necessary, so that I can lay track directly across it.  I start 10" back with a joiner pair and lay a full length of flex across the deck.  When it all lines up, I start building the understructer to support it and the abutments.  That could be blocks of wast bench-building wood, foam, cardboard shims, cedar framing shims...whatever keeps it snuggly in place.  If I have to trim the legs a bit, so be it.  I can build extruded foam footings, say concrete sills, or have them sit on 'mud sill's (especially timber trestles). 

Once the bridge is firmly supported, held at the ends by abutments, and can have the scenery built up and finished prior to adding trees and ground foam, I do exactly that; start using plaster, spackle, putty, whatever I need, to get the terrain shaped.  Add dyes or paint as you go so that it looks earthy.  Then, spray with a fixative of your choice and sprinkle, and blow, ground foam of at least two colours and at least two degrees of coarseness. 

 

 

 

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Posted by doctorwayne on Saturday, February 22, 2020 1:55 PM

Thanks for your kind words, Trainzman2435.

Trainzman2435
...On your tall steel viaduct picture, about what are the sizes of the pyramid shaped concrete pillars you made there?...

I'm assuming that the one to which you're referring is the taller of the two that appear in the same photo, as the ones for the bridge, now hidden in the woods, are a variety of sizes, due to the terrain.  Most of the latter are inaccessible for measurement. 
I would guess that for real concrete footings, the taller the concrete portion, the larger the footprint of the concrete base would be.

Here's a photo of one of the the "concrete" footings...

...and, as you can see, is about 4'6" tall over-all.  The base is about 4'x4' square and 2'6" high, while the angled portion is 2' high, and its top 2'x2' square.

It has been a number of years since the bridges were built (more than I care to admit Embarrassed) and I can't recall if the ones not in the river bed are fully-modelled or only partially-so, with their bottom portions simply cut to suit the terrain.
My intention is to forest pretty-well all of the terrain on either side of the river, and when the "water" is added, it will be, at most, about 1/8" of Durabond 90 patching plaster.  The bases of the towers, other than those in the river, will become pretty-much unseen.

Since the Micro Engineering tower legs have a footprint of about 2'x2', that determined the size of the top of the angled portion of the footings, which leaves the overall height up to you - you could model a portion of the straight sides, or skip them altogether and assume that that portion is "underground".

The reason I made all of my bridges removeable is both to allow access for occasionally cleaning the "water", but more importantly, for adding the trees and undergrowth necessary to complete the scene.  The area with the two bridges is somewhat accessible from the corner of the backdrop, but some areas will be reachable only by me actually being on the layout.

Wayne

 

 

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Posted by Trainzman2435 on Sunday, February 23, 2020 8:46 AM

Wayne, thank you sir for the information, it really helps me out a bunch!....Big Smile

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Posted by Don Z on Tuesday, February 25, 2020 9:55 PM

Since you've built open grid and covered it with plywood, why not cut out that section of the benchwork and lower it so you can keep the height of the bridge as built? Instead of attaching vertical risers that go towards your ceiling, invert them and let that section of the bench extend down towards the floor. My 2 Cents

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Posted by mbinsewi on Wednesday, February 26, 2020 12:45 PM

I get that Don, but he'd also have to rework the facia area, to create a "drop" in the bench work that looked like it was anything planned.  Which is probably what I would do.  A simple rework of the bench, and it's done, ravine built.

I'm not sure if the OP is up to that.  I guess we'll find out.  Trying to give him some "it will look alright" alternatives.

Mike.

 

  • Member since
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  • From: New Brunswick Canada
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Posted by Oaks Junction. U.K on Friday, March 6, 2020 9:40 AM

Cut two rectangles out of the base board and let the piers pass through, resting on two "new" pieces of baseboard below. Scenic around the peirs and only readers of this forum wil ever know.  

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Posted by TBat55 on Friday, March 20, 2020 6:15 AM

keybd keys for feetI used old keyboard keys for concrete footers.  The keys just pop off and have the right angles.  Put some putty on top then paint.

Terry

jjo
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    March 2020
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Posted by jjo on Tuesday, April 7, 2020 8:28 PM

Love those bridges!!! Very nice work!

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