Building Trestle + Girder/Truss Combo Bridge HO

Model Railroader Layouts and layout building
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The layout in the basement is a work in progress, and completing a bridge on one of the main loops is necessary to allow rail traffic to proceed. The layout runs along a shelf, and there are loops at each end. My idea for the bridge is to have a three span bridge with a wooden trestle approach on one side. The 3 span portion of the bridge is made up with a deck truss in the middle and two shorter deck girders on the ends. The bridge will cross a small creek with an adjacent road, and the trestle approach will be in the flood plain. I’m basing my idea on a couple photos shown below:

Old Milwaukee Road bridge in Ilene, IN

Minneapolis & St. Louis Railway Minnesota river crossing

I’ve decided to try my attempt at scratch building the trestle approach. Due to space, the trestle approach will likely start on a curve (26" radius) before straightening out.

I’ve done a lot of digging around to help me figure out how to go about making the trestles. I plan on making a jig to make the bents easier. I’m looking for more tips and suggestions on building the entire bridge, including the truss/girder and trestle approach. I’m interested to learn more about making stone bridge supports, which I’d like to use for the bridge itself. Also, I’m looking for tips on hand laying the rails on the bridge as well.

Thanks!

John

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Is it me or does the girder span on the far left not look level? I remember one bridge similar to that I modeled once, for some reason I couldn’t get that thing to be level for the longest time and it drove me nut’s. Now I realize I could have just left it the way it was.[(-D] I also like the big beaver dam on the left.[swg]

John, Dr Wayne on this forum has threads on making poured bridge piers so a topic search may be in order using the search function. I did make some piers out of foam a couple years back and other than my poor weathering job, I was happy with the way they came out.

I used a piece of “I beam” to push in to the foam to form the stone blocks.

Here they are under the bridge. The colours and weathering look much more subtle in person, but they are still a work in progress.

Are the steel girder portions of your bridge going to be on the curve or just the wooden part?

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Brent, nothing in ‘rail land’ is planar for more than a few dozen feet. Even a bridge deck will have some elevation changes, if very minor and negligible. I don’t really see much of a shift except possibly a fraction of a %age in grade when I lay the edge of a piece of paper across my screen to see if they align.

A jig will help a lot, but so will one of those plastic hobby miter boxes and a razor saw, especially for stringers, girts, sway braces, etc.

There is a method for laying the stringers on a curved trestle that you and I can discuss via email if you wish to follow the Rio Grande style.

Build he deck first, to length and to curve, with its top surface down on a board that is truly flat and portable. From there, you will build bent frames invert them, and glue them into place. You’ll prop them up so that they dry perpendicular to the stringer roadbed. From there, you just add girts and sway braces.

Very important to remember to build the various bents long enough to reach into water, terrain, or to the sills. Think this part through. Build the roadbed approaches on either side, then measure the distance from your roadbed surface where they meet to the material/surface/water below. For gullied terrain, the middle bents tend to be the longest. You trim off what you must as you do inversion trials and set the upright trestle in place. When it finally sits fully on the prepared abutments, you then make the sills or footings tidy with added terrain goop or whatever…another layer of epoxy water so that they look immersed.

For rails, pre-bend them, including the inner guards. Lay bridge ties and glue them with either Ambroid, or wood glue, or gel CA. Then do the same with the bent rails, but I would use the gel CA only.

When building your trestle, think about at least one refuge with sand barrel.

-Crandell

Edit- I found a link whose name has been cha

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It looks like the piers are sinking into the water.

Rich

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Crandell, you are right, I have become much better about being too fastidious about things in this hobby and have learned imperfect usually looks more real.[8-|]

Actually, did you notice that the second pier is different than the other three? I wonder if it has been replaced once already. Maybe an out of control Beaver Dam that was sprung loose at high water took out the first one.[(-D]

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Brent,

That is correct. That bridge is the Minneapolis and St. Louis bridge, and it’s also out of alignment due to the peer shifting in the mud. The bridge was stated to be demolished, and I’m unsure if it has been removed yet. The line concerning the bridge was abandoned by the Union Pacific in 2008, and the local governments are trying to preserve the ROW for a rail trail, including a new bridge. Here’s another photo of the deck:

While digging through the internet to find information to help shape my bridge scene ideas, I stumbled across project photos of the replacement of the previous bridge I showed, which spanned the White River in Indiana. The bridge was built in 1899, and recently, it was associated with speed restrictions and wasn’t able to support the tall intermodal freight due to height restrictions. In their photos, it appears they are replacing the trestle with concrete spans, and replacing the truss with massive steel beams.

Project Photos: http://www.in.gov/indot/3375.htm

Using that I beam is a pretty cool idea, and those piers look good! I noticed the corners were rounded at the bottom, but a little bit of landscaping will easily conceal that. From that picture it looks like a good representation of a stone pier, but in person, does it stick out as looking like a block of foam? Also, does it compress or flex when a train goes over it? I did see Dr. Wayne’s thread. I plan on doing the abutments last, so as of now, I’m considering carving foam/wood or going the molding route.

-John

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Here’s an update on my progress:

It’s been a tedious process. I’ve been spending a lot of time reading threads, looking at pictures, and watching youtube videos to better refine my bridge scene idea. Before I get much further, I should mention that the layout models the New York Central around 1950s to 1970s. The scene I wanted to model included a long, mostly low trestle leading up to medium (< 90 ft) steel bridge spans over a non-navigable river. The bank on the trestle side would be more shallow whereas the other bank would have a steeper slope, so the steel spans would terminate into a concrete/stone abutment. At this point, I’m planning for steel spans to have a maximum height of 50 HO ft while the trestle will be about 15 HO ft tall and slightly dropping off at the end of the trestle. Fitting a road under the bridge will likely be too tricky, so I’m not really considering it anymore.

At this point I created a CAD drawing of the bents and made some jigs. I had to be very careful with the glue so as to not accidentally fuse the bent to the jig. I initially only included an extra .25 inch for anchoring the piles into the landscape, but after reading Crandell’s comment, I added an extra inch to the rest. I’m thinking of drilling holes into foam to anchor the ends. On the left is a CAD drawing I made of the stringers, and it only shows half since I’ll need a larger paper size to print the entire arc. I’ll definitely add the barrel. I still need to figure out how to go about adding the ties to the stringer. I’ll likely make another jig.

I played around with different stains and settled on a dark walnut color. Above is a close up of the result.

For bending the rails, is a tool really necessary or can a little hand bending get me 90% the

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John, just like my foam mountains, one cannot tell they are foam at all. In fact people are really surprised when I show them the things I have made out of foam. I have even sanded down foam and painted them to look like concrete piers and was very satisfied with the look.

The foam piers do not move at all when a train goes over and they are not even glued into place yet. I used a bridge track on this scratch built bridge and it is glued to the bridge. I think the strength comes from the track being glued to the bridge as I have run trains over the bridge with no piers under it and there was movement at all. The bridge butts up to spline roadbed on either side and is removable.

I needed a curved steel span that was on a 2% grade, couldn’t find one in the catalog, so I had to make my own. Here are a couple of pics.

Note the curved support for the track. Naturally this required a wider bridge to be built.

Stuck on the fake rivets.

Here is another bridge I had scratch built for the spot, but due to some mathematical errors on my part, a rework was required. [:-^]

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Brent,

I like the way that turned out. What material was used for the first bridge, styrene or stripwood? Those diamond patterns turned out pretty good.

I think I’ll also make the bridge removable, as I’m not sure what complications can arise when finishing the scenery or even cleaning. What were the fake rivets made out of? They look just like basic circles, but making them looks difficult.

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Hi John.

The bridge(s) was made from the scrap box with parts from

Central Valley, (beams)

http://www.cvmw.com/bridges.htm

Micro engineering, (girders)

http://www.microengineering.com/index.htm

Atlas, (Girders)

http://www.atlasrr.com

The rivits are decals from Micro Mark. Applied and painted. Easypeezy!

Applied on the right side in this photo.

I also used strip styrene here and there to help clean up some of the lines a bit.

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Ed note: reposted from duplicate post.

Hello All,

I’m assuming you are building in HO since you did not specify a scale.

For the three bridge spans you can use commercially available kits. Central Valley Model Works offer several bridge kits that you can place together. There are also bridge kits available from other manufacturers that would work too.

In a recent edition of MRR there was an article on ‘Scratchbasing’ a bridge (MMR; June 2015, pg. 48).

For the trestle bents I’d definitely build a jig. From the photos it looks like they are all about the same size.

For some of the parts of the bents you might consider buying wooden matches. They come in several sizes, are pretty consistent in thickness and length and closely replicate common timber sizes. Soak them in warm water to remove the flammable tips and then stain them.

For the look of creosote I use Minwax stains. I combined one part Ebony 2718 with two parts Red Mahogany 225.

I put the items to be stained in a zip-top bag (the heavy freezer type) and add the stain mix. I then remove the stained items to several sheets of news paper, using a Nitrile solvent resistant glove.

You can vary the amount of stain to achieve your desired results.

As far as the stone bridge supports you might look at commercially available items from Chooch Enterprises or other manufactures.

You could purchase them pre-made or you could purchase the sheet form and fabricate them yourself.

For the plate girder sections there are many options from scratch building the components from sheet styrene and rivet details to purchasing kits.

I was at a local train show and I found two Atlas Plate Girder Bridges for $1.00 each. I cut the track beds off and now have 4

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JJ,

Thanks for the great tips! I’ll look into those books. I like the zip-lock bag idea. When staining the stripwood likes to float, so it’s easy to get an uneasy stain if not being careful. I settled on a dark walnut stain from Minwax. I tried some other darker stains, but you can see the results of the dark walnut stain in the photos above. At this point, I’m leaning more towards doing more scratch building on the bridge. For example, bridge abutments might be tricky to get in the right configuration, so scratch building may be easier.

This last week has been quite busy, so unfortunately I haven’t made as much progress as earlier. However, I’ll be sure to post pictures and updates as I progress more.

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John,

Found this book on Google books (free, public domain) under Railroad Bridges.

A Treatsie on Wooden Trestle Bridges and Their Concrete Substitutes by

Wolcott C. Foster, 4th edition (1913).

It covers a wealth of info on trestles up to 1913 with photo, drawings, info,

etc. on a large number of U.S. rr on pages 1/236.

Part II has standard trestle plans and most have timber dimensional data on

pages 237/362. Trestle on a curve is on pages 328/329.

Section V has concrete trestles on pages 363/393.

Lloyd

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Hello All,

Great work!

As for the abutments Jeff Wilson’s book “The Model Railroader’s Guide To Bridges, Trestles & Tunnels” (with the green cover) has an entire chapter on fabricating thsese.

One of the methods he discusses is fabricating these out of sheet Styrene that has a stone pattern. The ones he makes are square or five-sided (with a cutwater) then capped with plain sheet Styrene to replicate a concrete cap. You could easily make them three-sided with a cap and place them where needed.

You could use other commercially available sheet stock with stone patterns.

Another method mentioned is casting the abutments not with Plaster of Paris but Sakrete Anchor-Bolt cement. Then with a rotary tool (AKA Dremel) and dental picks you can make the desired patterns.

Keep up the great work and keep those updates coming.

Hope this helps.