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The Truss bridge in the foreground of the attached picture was made by my son when he was in high school for an advanced AP class where the particular subject under discussion at the time was calculating loads. It was not copied from any specific design and it was first drawn in a Mechanical Drawing class full scale with Autocad and then the individual 1/8” balsa pieces were tacked right onto the blueprint and glued together with Elmer’s. It supported a 10 lb weight which was the assignment. My son told me it was a lot of fun, especially on Test Day when they got to laugh at some of the other class member’s attempts that crumpled in spectacular fashion.

The timber trestle is my own design that I made and not prototypical in that each bent only has three vertical supports (to save on cost).  It was a bit involved since I chiseled notches (a Dado Joint, I think it's called) into each piece for each cross section and glued with wood glue. I used Microsoft Visio to create a full scale drawing and used ¼” basswood pieces that matched up to the drawing. The trestle itself actually supports the roadbed and track above but the difficult part was in actually installing it since the roadbed was built and the the track was laid first instead of visa-versa.

All in all, I’d have to say since I managed to do it, it can’t be all that hard. Jigs weren’t necessary but the drawing in each case was critical. I’m sure others in the forum with much more elaborate and prototypical examples will post pictures and descriptions but my goal was to give the look and “flavor” of a timber trestle. The scenery is still under construction and is currently the bane of my existence.          


  

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  • Trestle & Bridge

I built this O scale 30" truss bridge using Plastruct's HO plans (no O scale plan was available) enlarged at a FedEx Office store and figured out the BOM from the enlarged plan.  That was 15+ years ago; Plastruct now offers the bridge kit in O scale for $39.95.

The bridge is extremely strong.  It fell from about 6' and landed on hardwood floor.  Some pieces separated but went back together easily and only needed a few cosmetic pieces fabbed or reattached.

When I built mine, I used a Zona razor saw and an aluminum mitre box.

 

KIT-2.jpg

https://plastruct.com/shop/tra...eries-kits/kit-3002/

Picture shows the scratch-built trestle and through-truss bridge on my 10'-by-5' layout that is the subject of an article in OGR Run 304. Both bridges are 24 inches in length, constructed from basswood, and easily removable from the layout. I made an accurate sketch of the truss on a sheet of graph paper, determined the geometry and dimensions needed for construction, marked and cut all truss members with a razor saw/miter box, and filed or sanded until the fit between the upper and lower horizontal main truss beams was just about perfect. Assembled the trusses on a glass plate (covered by waxed paper) to maintain flatness using masking tape and weights to hold pieces in position until the yellow carpenter's glue dried. Similar process was used to establish geometry of trestle bents. Since the bents were small, I marked a thin sheet of basswood with locations of the "vertical" beams, taped and weighted the pieces down flat and glued them to the top and bottom cross members. Could have made a small jig for the trestle bents but did not think it was necessary. Then inverted the bents and glued them to the longitudinal members with spacing 1-1/4 inches (same as rails). When all bents were in place, carefully turned assembly upright and installed diagonal/horizontal braces. The longitudinal rail support members rest upon "stone" abutments at each end. Truss bridge members - all cross sections 3/8-inch wide with depths of 3/16, 1/4 and 3/8 inches. Trestle bent "vertical" members and longitudinal members supporting rails (both bridges) are 1/4 inch square cross section. Used a steel rule and small 90-degree triangle to assure perpendicularity of all members on both bridges. 

MELGAR

MELGAR_PHOTO_03_VALLEY

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Last edited by MELGAR

If you are building a one of a kind deck or bridge jigs are not really necessary. You can make a spacer to align deck ties in both cases.

If you build a lot like I do then a glue jig for the deck ties is the fast an easy way to go. Among other things it ensures all decks are the same exact width.

I have no photos of my jigs handy but all consist of dadoes cut into plywood that fit the deck chords. I cut shallow dadoes on the chords that accept the deck ties so there is no need for spacers. The chords are placed in the jig and the ties are glued in place with white wood glue.

For truss / girder bridges I have diagrams that show where the vertical posts go for the standard sizes. I attached a sample pdf.

Below are some photos

Joe

Bridges 007

O Scale Girder Bridge with Railing [1024x678)

O Scale Truss 5

Bi Level Truss 3

 

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Bridges are a great visual element and provide a bit of drama.  When my family lived in Milwaukee many years ago my dad would drive the family down to a canal near the lake where the CNW had a crossing swing bridge.  There was a building that was either a switch tower or an interlocking tower trackside.  I don't have a place for that on my layout but it would be a great project.

I have scratch built girder bridges based on scale drawings from google research.  I will try to find photos.  I made this single track 22 inch bridge with blocks between masonite sides.  

girder%20bridge

This a post I made when I was redoing my layout.

Making progress on the deck girder segments:

The decks are assembled and painted. I'm making support columns out of cheap shelf strips that I will paint light green.

I'm not sure if the supports are here to stay.  For now I plan to add 2 more supports in each of the two 36 inch sections and 3 more in the 48 inch section. The bridge is to allow rail service to the adjacent buildings but also storage for some cars.

20161021_17324620161021_173223

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Last edited by pennsynut

On my old layout I scratch built my own trestle bridge.  I forget what size wood dowels I used but it looked to be right.  I built a jig for all the bents so everyone would be the same.  I just remember it took a long time to stain each piece of wood and letting it dry before gluing it all together.  I think I watched the complete seasons 1 & 2 of Hogans Heroes staining all the wood.  I was able to save it when taking down my old layout but haven't really found a great spot for it on the new one due to this being curve with 81 and 72 whereas the new layout is using 108 outside radius.   If I can use it I will have to cut the height down in size.  11057725_10207629444400065_9152403740298763045_o11807269_10207629444720073_5745478855969936335_o

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I scratch built this trestle last year. It is 75" long, 20" high and the deck is 10" wide. It took the better part of the year, working off and on. I first researched trestle design to get the angles and supports correct. I then made a scale drawing which I then transferred to a template. I planned on 5 bents so I designed the template to handle all five of them. As a retired cabinet maker I have a shop full of oak so that is what I used. I milled planks of oak down to 1/4 x 1/4 x 4 for the main structure. Everything was then stained. I also made a full template of the arc to use when making the deck. It took me about 5 weeks to make the 20 bents using lots of saws, sanders, pin nailer glue. I then had to design and make a template for the deck, another week. The deck was assembled in six sections, all dowled together. Finally the bents were attached to the deck.IMG_0500IMG_0503IMG_0504IMG_0505

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MELGAR posted:

Picture shows the scratch-built trestle and through-truss bridge on my 10'-by-5' layout that is the subject of an article in OGR Run 304. Both bridges are 24 inches in length, constructed from basswood, and easily removable from the layout. I made an accurate sketch of the truss on a sheet of graph paper, determined the geometry and dimensions needed for construction, marked and cut all truss members with a razor saw/miter box, and filed or sanded until the fit between the upper and lower horizontal main truss beams was just about perfect. Assembled the trusses on a glass plate (covered by waxed paper) to maintain flatness using masking tape and weights to hold pieces in position until the yellow carpenter's glue dried. Similar process was used to establish geometry of trestle bents. Since the bents were small, I marked a thin sheet of basswood with locations of the "vertical" beams, taped and weighted the pieces down flat and glued them to the top and bottom cross members. Could have made a small jig for the trestle bents but did not think it was necessary. Then inverted the bents and glued them to the longitudinal members with spacing 1-1/4 inches (same as rails). When all bents were in place, carefully turned assembly upright and installed diagonal/horizontal braces. The longitudinal rail support members rest upon "stone" abutments at each end. Truss bridge members - all cross sections 3/8-inch wide with depths of 3/16, 1/4 and 3/8 inches. Trestle bent "vertical" members and longitudinal members supporting rails (both bridges) are 1/4 inch square cross section. Used a steel rule and small 90-degree triangle to assure perpendicularity of all members on both bridges. 

MELGAR

MELGAR_PHOTO_03_VALLEY

Nice work - very precise!

I took Plastruct's bridge kit and drastically modified it making it from a through truss bridge to a deck truss bridge. This change required me to re-draw the entire bridge in Coreldraw, print it out in 1:1 scale (1:48) and build the bridge directly over the plans using T-pins like building a model airplane. My work bench's top surface is Homasote which is a great surface to hold T-pins. I tape the plans to the Homasote and then cover with some polyethylene film so nothing sticks to the plans. I used the H-, I- and T-Beams that came with the plastruct kit, and also used the sheet ABS for the gusset plates. Instead of embossing rivets into the plates, I used Archer Decals rivets which worked nicely. I used Plastruct's instructions on handling the joinery details, but applied them to my plans.

To cut the gussets, I printed out the gusset patterns on plain paper, temporarily adhered it to the ABS and used a scissors to cut them out. Gluing gussets to the bridge was all done with Bondene liquid plastic cement.

Truss Bridge Construct 02

The top and bottom longitudinal members have to be continuous pieces if possible. The top rail is Ross Bridge Rail with the guard rails included. The design of the deck truss has another set of longerons directly under the running rails. 

Truss Bridge Construct 06

Archer Decals applied. The gussets actually comprised all the primary strength of the build. The individual joints of the members to each other was secondary.

Truss Bridge Construct 08

The twin bridges are very strong and could probably each support 50 pounds or more. A 12 pound loco going across causes no deflection at all.

IMG_1406

Here's a drawing I made. Also attached is a full-size PDF of the same. You can print it out on multiple pieces of paper and tape them together to make the building pattern.

Modified Plastruct Truss Bridge

 

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Last edited by Trainman2001

I think Jim Barrett's articles mentioned above should be the basis for anyone starting out with the intent to build a trestle/bridge. What REALLY amazes me about Jim's work is that he built 3 or 4 trestles on a slide-out section of his layout that detaches from the fixed portion of the layout....and then slides right back in and lines up perfectly. Only Barrett would build trestles on wheels! But all joking aside, his movable trestles are a remarkable piece of basement modeling. Some of the final details about hiding the joints are in the 12/2018 issue of OGR.

Sometimes I have to read his stuff twice because it is just so valuable that I want to make sure I remember it.

Don Merz

 

awhile back I was able to acquire a lot of scrap aluminum sheet stock so I designed a few bridges and did some horse trading with a few friends for time on a waterjet

the first pic is the 20 inch truss and 30 inch bridges102_1941

the next two pics are of my 45 inch arch truss bridge102_1943102_1944

The last two are of a 105" arch/suspension102_1987102_1989

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Images (5)
  • 102_1941: 20 and 30 inch bridge
  • 102_1943: 45 inch arch truss
  • 102_1944: 45 inch arch truss
  • 102_1987: 105inch arch arch suspension
  • 102_1989
Last edited by old_toymaker

I scratch built these bridges for an out door suspended layout under the covered patio attached to my workshop. The wood bridges are made from oak, and the open deck girder bridge is made from soldered steel. The metal bridge was modeled from a bridge nearby. I have access to a shop full of sheet metal tools, so it was fairly easy to cut all the necessary parts. The soldering was a bit of a challenge.

 

 

Trains 084Bridges 07 31 14 003Bridges 07 31 14 007Wood bridges 008

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Great posts and pictures above.

@Trestleman1 created an amazing trestle seen in the link below.

https://ogrforum.ogaugerr.com/...look-at-this-trestle

As someone who has not built a trestle before, I found it interesting that he built it upside down in order to keep the track surface on a level plane.  Once it was flipped over, he could shim/fill any gaps between the benchwork and the base of the trestle.

TRAINMAN2001:  If the question is for my bridges the (beams/girders) whatever you call them are three pcs pressed together and then the bridges are bolted with 4-40 screws. Some holes are tapped and some are nuts and bolts. The 105 inch bridge has about 700 bolts in it and is an actual working bridge, that is to say without the arch and suspended rods the road bed would bow badly and probably just fall but as it is I had 3 - 25 pound bags of shot in the middle and it never sagged at all so I guess it will hold my trains . 

102_1815

This is what I bought for screws. I buy them 1000 at a time from bolt depot

102_1730102_1731

102_1732

you can see the slot in these pics how the beams fit together. the width of the slot has to be cut close so the center will press in just tight enough but still stay together

102_1793102_1816

On the long bridge I had to join short pcs because l I had was scrape  so I mad some doubler plates to cover the joint's

102_1884

You can see them here on the 45 inch bridge

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Do not have a trestle on my layout, but here are some pictures of the real thing.

March, 2011  UPRR Coal Train in Colorado on the North Fork Branch, crossing the Bear Creek Trestle on it's way to the West Elk Mine.

IMG_0898

This Classic Trestle is in Northern Idaho.  I took this picture in Nov, 2010.  I'm not sure but I think this line my be abandoned.

IMG_0821

Steve

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The bridges are all screwed and bolted together so that they can be taken apart in case we move when I retire or if I put them up for sale

I have the plans in a cad program and .dxf files and the main drawings in .dwg  I could add all the dimensions to the drawings. It would take a little time but I will do it if someone wants a drawing. The difficult part is getting  the use of a machine to cut the parts out.

Last edited by old_toymaker
MELGAR posted:

Picture shows the scratch-built trestle and through-truss bridge on my 10'-by-5' layout that is the subject of an article in OGR Run 304. Both bridges are 24 inches in length, constructed from basswood, and easily removable from the layout. I made an accurate sketch of the truss on a sheet of graph paper, determined the geometry and dimensions needed for construction, marked and cut all truss members with a razor saw/miter box, and filed or sanded until the fit between the upper and lower horizontal main truss beams was just about perfect. Assembled the trusses on a glass plate (covered by waxed paper) to maintain flatness using masking tape and weights to hold pieces in position until the yellow carpenter's glue dried. Similar process was used to establish geometry of trestle bents. Since the bents were small, I marked a thin sheet of basswood with locations of the "vertical" beams, taped and weighted the pieces down flat and glued them to the top and bottom cross members. Could have made a small jig for the trestle bents but did not think it was necessary. Then inverted the bents and glued them to the longitudinal members with spacing 1-1/4 inches (same as rails). When all bents were in place, carefully turned assembly upright and installed diagonal/horizontal braces. The longitudinal rail support members rest upon "stone" abutments at each end. Truss bridge members - all cross sections 3/8-inch wide with depths of 3/16, 1/4 and 3/8 inches. Trestle bent "vertical" members and longitudinal members supporting rails (both bridges) are 1/4 inch square cross section. Used a steel rule and small 90-degree triangle to assure perpendicularity of all members on both bridges. 

MELGAR

MELGAR_PHOTO_03_VALLEY

Wow - really cool!

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