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Some early prilimiary sketches showing some thing about the engineering. I worked closely with a retired civil engineer who helped me create a scene that would be accurate but also visually interesting. Patterned after several St Vrain crossings I think we have a solution that will be visually stimulating as well as functionally authentic.  Era is 1950's... 

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Erik,

Congratulations. Excellent example of using numerous freehand sketches to visualize bridge scene prior to actual construction. Shift angle in rail right-of-way adds a lot of visual interest to the overall scene. Wish more people would adopt your sketch technique before attempting to build their layout scenes. 

Bridge design and details very convincing!

Very nice Erik.  Here, east of the big muddy, we often see remnants of older bridges aside of newer and larger ones.  Many times all that remains of the older bridge is the stone bridge piers in the body of water (if it's not navigable). 

Interesting sidelight, when Newark Bay was dredged thirty years or so ago to make it more accessible for larger vessels, they did underwater demolition to get rid of the footings/ middle piers from the old Jersey Central draw bridge (which was actually twin lift bridge spans).

Kewl stuff and a sweet bridge, that OMI piece.  Wished I could justify one.

Too bad Train Cat won't make a shorter (25'-40') version of their very common AmBridge plate girder bridges in O scale.  Yes, I did ask several years ago but was warned not to get pushy or the owner will just ignore you.

Those would be AWESOME for yours and for many projects.   The capture the feel of the real built-up nature of these perfectly.

As a bridge troll, I can tell you just when you think you've seen it all with respect to bridges, you come across something you thought you'd never see. There was an old Pacific Electric steel truss bridge in San Bernardino across the Santa Ana River that started out as a wooden trestle. On the south side of the bridge, the trestle pilings were all in place leading up to the concrete footings for the steel bridge. Best guess is that the bridge got washed out in one of the floods that hit that river (one in 1938 took out the trestle on the ATSF Redlands Loop). Somewhere I have photos I took a couple of years before they took down the bridge to make an access road (a less attractive concrete highway bridge). I've even seen bridges built from decommissioned 89-foot flat cars. Go figure.

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Last edited by Erik C Lindgren

Erik, it looks like John is deep in thought thinking this scene would look so much better with about 4 or 5 Lionel girder bridges in a row.  So to help you guys out I would be willing to send you a 1/2 dozen of those and since you won't be using the 2 bridges pictured I think I might find a home for them. Seriously that scene really is looking super. Don't forget Scale City Designs has bridge shoes avail if you need them for the girder bridge if you don't want to take me up on the more than fair trade I offered.

Erik C Lindgren posted:

I'm blushing Matt 

oh it's completely prototype and a complete story line behind it. When I get time I will elaborate. 

 

Thank you 

Makes me want to revisit a spot on the old Redlands Loop where the ATSF line paralled the SP line to Crafton. There were two small bridges across a creek -- one a full wooden trestle (ATSF) and the other more modern for the SP line (probably wood with concrete footings. The ATSF trestle is a ruin but is still there; all that's left of the SP bridge is the footings.

Eric....I have that same through plate girder bridge but in black.   What a beautiful model!    I've talked to Peter through that famous auction site about doing these with square end girders, and he is going to look into possibly doing these at some point in time........   Please keep us posted with pictures as you make progress in your project.

Erik and i discussed some ideas and he made a sketch (above) and i set out to design and build the modules to support it.  Comments were made about prototype accuracy,  so Erik did some research.  Guess we didn't miss it by much judging from the photos he found.  Stay tuned,  there may be a 3rd rail in the picture yet!  Prototype: Alamosa/Antinito line of the D&RGW,  San Luis valley branch.

AGHRMatt posted:

Erik:

Do you have any photos of the framing under the foam in the bridge module set? I'm curious how the foam is supported.

I responded to John for you he will likely show you what's involved in the design. 

This is from his article about the engineering earlier last year:

Lightweight Module Construction

A little history here will explain why this type of module construction came to be. Forty years ago N Trak was breaking a lot of new ground with the idea of modular layouts. They could be set up and displayed in many venues previously unavailable, like shopping malls. The hobby shop with the layout in the front window was getting rare and shopping malls were the the new meccas of retail trade. A lot of modeler got their start with these groups.

My club at the time was building a HO layout based on Marin County railroads in an old dairy barn. We decided to build a modular layout to display at the county fair. Construction was based on the N Trak standards, 1x4s with 1/2” plywood top. Sturdy but not very light. Legs were an issue as it was difficult to prevent swaying when they were leaned upon without getting involved with a lot of bracing. I even drilled lightning holes in th 1x4 crossmembers (actually 1/2”x4” plywood) in an effort to cut some weight. Later the 2x2” legs were replaced with 3/4” EMT conduit with angle braces to improve stability. Both efforts were marginal improvements.

My next effort was based on 1/4” plywood. Sides and ends were laminated with extra plys where the strength was needed. Legs were folding 2x2s. Not bad, it was lighter and easier to set up but still not quite right.

With my move to Colorado and switching to 1/4” scale came the opportunity to start over. Everything module effort to date had multiple toos problems:
too heavy
too fragile
too difficult to set up

Experimenting with a portable F scale layout introduced some new ideas. First to go was the legs, simple sawhorses under the joints replaced attached legs. Set up time was dramatically reduced. Next to go was the bolts/C clamps tyeing the modules together.

 

 

 

 

to continue about construction of modules:

We use spring clamps w/ locating dowels between sections,  quick and easy.

Actual module is 2" insulation extruded foam (not white beaded stuff) that comes in pink or blue,  depending on manufacturer.  Default module width is 22".  Beam strength is provided by 2 3/4" strip of 5mm underlayment plywood on each side.  End boards a 3/4" lumber to provide strength for dowels & clamps.  Stringers of 3/4x3/4 wood are used about every 12" to control sag between sides.  This is where the 2 3/4" side depth comes from.  Titebond used for wood/wood joints,  foam/wood joints are secured w/ our secret ingredient, Gorilla glue!  This results in a bonded structure that resists twisting and bending.  A 5' module will support my weight in the middle (165#) with very little sag.  A bare module weights appox 5#.  #12 bare copper busses are strung under the track for feeders,  SAE 4 prong plugs (trailer connectors) connect each module.  Two Pony 2404 or equivalent spring clamps grip lower lip at joints where a lightweight sawhorse supports the joint. 

Two plywood boxes (24x24x40") were added to the center of each side of our 9x35' layout for added stability.  A casual bump doesn't phase it.  They also serve as control stands and power centers.  A fixed clamp joins two modules on top and electrical connectors tie into the buss.

We will work on making a video of the construction process.  Construction time is about an hour of actual work,  added time for glues to set.  Assembly is done on a fixture to insure squareness and assist clamping.  Further questions can be submitted to our website: coloradooscale.org,  contact us form.

Setup time for 16 modules is about an hour for one person,  longer with help.  Track ends at module edge,  rails are soldered to screws or nails in the sub-roadbed (spline).  This method has been in service for over a year (5 shows) w/o any problems.

 

 

it just boggles my mind in looking at some of the photos...but yep it's a model.  This is coming together quite nicely and really demonstrates what proper planning and execution will get you.  The bridge in it self is a masterpiece but when combined with all of the other elements of this scene......well mind blown. 

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Showing the authenticity in these fine brass bridge models. 

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Timber supports will be in place of the red painted piers in this photo. 

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Flex track laid in place for reference only  

John johnson has begun the track work phase of the bridges. We ordered Mt Albert bridge ties and other lumber for the project. 

Bill of Materials 

MA335P24 8x14 will double up for 14x14 pile cap 
MA342P24 10x18 stringers 
MA319P24 3x12 sway bracing 
MA322P24 4x8 guard timber 
MA324P24 4x12 shoring timbers 

MA382 8x8x10' bridge ties (500) 

Dowels will suffice for the bridge piling. 

We continue .... 

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Last edited by Erik C Lindgren

Thanks guys...

Johnson wants to hand lay with tie plates doing the trackwork. I agreed, I used Monster Model Works per Johnson's request. They had the tie plates that Johnson wants or meets his expectations to his custom made spikes.

I would also like to recommend Right of Way for track spikes and tie plates however Johnson could not find the square opening variety he was after at ROW.  Jay Criswell at Right of Way will be supplying us with all the rest of the trackwork detailing. I will be generating a BOM for him this week. 

 

These are the tie plates offered by Monster Model Works:

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http://monstermodelworks.com/o...-138-148-8-hole.html

This is an opportunity for Johnson to bring his enthusiasm with P48 in on this project. When the exhibit is set up the viewer is close enough to the model inches at times that leaving off crucial trackwork detail such as tie plates is blasphemous, for a lack of a better word. 

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I hope this project will be pleasing to the viewers and history buffs.. oh and the toy train enthusiasts. 

I will be back with more, the saga continues. 

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Last edited by Erik C Lindgren

Hi Bob,

From my research the walkways were originally designed for crews and if the bridge was within range of a turnout for the obvious reasons, cutting cars and the like. The placement of the bridge on the layout is not within range of a turnout in our simulation. Furthermore a walkway encourages trespassing and walking the span. It was decided to drop the walkway assembly as it was easily removed and I suspect intentionally left that way for this reason from MS models Korea. I think the bridge will look far better without the walkway as most of the bridges I've seen in this design don't have them any longer and this holds true into my era of modeling the 1940's and 50's. Thank you for asking Bob I really appreciate the comment. 

Erik

Last edited by Erik C Lindgren

We have removed the original walkways from the truss bridge and are building a new deck using D&RGW standards for timber decks from the 40's.  Lumber is Mt. Alberts Scale Lumber (nice stuff) stained with felt tip pens (water based).  First black,  then texturing with a hacksaw blade.  Any fuzz is scraped/sanded off then a brown stain (touch up pens) is applied.  It's subtle,  but gives multiple hues to color.  Experimenting with a white felt tip pen to lighten without filling texture.  Deck assembly about half way across and moving along well.  Assembly delicate but not too fragile to handle so far.  Using Titebond glue which gives a little flexibility over the brittle bond of CA adhesives. 

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