Steel Trestle Supports

MTH makes some that they call SUBWAY supports.    

Jim 

You might find what you are looking for at Bridge Boss

Check out what Ross has.

http://rossswitches.com/maintowersection.aspx

Thanks, guys!  I really like the Ross design - that is very close to what I have in mind. I clicked through the site - is it a custom build or are they available as a kit?  I would definitely be interested in any other suggestions similar to the Ross design. 

Plastruct H and I beams is what I am using when I get to the point I need a bridge. No kits.....but easy to use.

Hello Blueline. The first two could work. How do I find them?  Dave, I may go the same route if I don’t find a plug and play solution. 

AMCDave posted:

Plastruct H and I beams is what I am using when I get to the point I need a bridge. No kits.....but easy to use.

Hello Dave. For the vertical load bearing H beams, will you use ABS or styrene?  Does it matter from a strength standpoint?

These supports are made from Plastruct parts, decks are from Ross. I had the same issue

of finding a commercial  kit along the  lines of the Micro Engineering  viaduct kit available

in HO.  I have had an opportunity to see the supports Steve from Ross Custom Switches

is offering, They are nice. Good luck, Mike

Rider Sandman posted:

AMCDave posted:

Plastruct H and I beams is what I am using when I get to the point I need a bridge. No kits.....but easy to use.

Hello Dave. For the vertical load bearing H beams, will you use ABS or styrene?  Does it matter from a strength standpoint?

ABS is a little stronger but if built like shown above either will work fine. I like the ease of styrene cutting and gluing. 

Mike, thank you for the pics - your design turned out awesome. I hope to mimic the end result. 

Dave, thanks to you as well. I was hoping styrene could be used for the reasons you mentioned. Sounds like it could. 

PRR Mike, would you happen to have the plastruct part numbers for those trestles in your picture?

They look very good.

Hi Steve, The bridge decks are by Ross Custom Switches and they are beautiful. When I built this trestle he had not yet

brought his trestle bents to market. I have had a chance to examine them at  The Big E show and they are also

well done.  At the time I built the trestle Steve Ross had not produced the narrower decks where the

trestle supports should be placed plus I wanted the larger box girder trestle look, so while the placement of the bents

isn't prototypically correct I like the look of the larger box trestle.  Construction was fairly straight forward.

I did make the trestle bents cant to the top for visual appeal. I also placed steel pins at the junctures

of the main I beams (A) and the cross beams (E) for added strength. I felt I needed more strength than I would get

using glue alone. The rods (D) are fitted loose and provide no structural support.

A:   Plustruct   Traditional ABS I Beams   B-24

B:   Plastruct   Open Web Truss-Warren Style 2   OWTA-24

C:   Plastruct  ABS Structural Flange  SAF-24L

D:  Plastruct  Solid Styrene Round Rod: Not sure of actual size,

E:  Plastruct:  Traditional ABS H Columns   H-8

Hope this helps, If I can provide any addition info, let me know, Mike

looks cool BUT structurally incorrect.

the long side girder could not be constructed in one piece as shown.

further what's the point of the transverse I-beams underneath the girders?? the girder would be supported on a base plate connected to the top of the truss support. there would be transverse girders or x-bracing connecting the side girders.

again looks cool.

thanks a bunch PRRMike.  Appreciate all  the details.  How tall are your trestles? 

A quick estimate I did comes out to about $300 in Plastruct parts.  More than I would have guessed.  This is for two trestles, each about 12-13 inches high.

These things add up, but the aesthetics are pretty darn good.

Steve

If you want to use girders as shown in the picture you may need only two supports that would reduce the $300 estimate.  I have no idea if that would accurate as compared to a real bridge or trestle.

Charlie

@PRRMike posted:

If you are interested in a more realistic approach (and my purpose here is NOT to belittle the achievement here, which is very impressive!), the fixes can be simple.

Do you see where the "shoes" are at the far left on top of the abutment (I think they are shoes there, but I cannot see them well enough to be sure)?  The shoes on top of all the supports need to be in the same relative place:  under the thinner portion of the girder.  The first girder is an 8-panel girder; the next one, moving right, is a 12-panel.  We cannot see the far end of the third panel, so we don't know what size it is.  A prototype placement of the piers would move them much closer together than in this set up with a wider distance between the piers at the ends of the girders.  Without the transverse beams, and with less distance  between the connected piers, the materials costs might go down (though you will need more shoes).

A basic facet of bridge design, in general, the girders (whether solid or truss) are supported on their ends.  Supporting them otherwise undermines the design.

Aside from the "rivet counting" I think this is a great looking scene and wouldn't change a thing. Great job!

Steve , Apologies for not getting back to you sooner. Here are the measurements for the trestles.

The 9 inch width was done to be able to able to span the narrow portion of the side girder in order to have the trestle piers support the bridge.

A little additional  background information on the overall design of the bridge. This is the classic reversed engineered structure. I have attached the track plan to help explain myself.

To improve train operations the plan needed to have two reversing cross-overs. As you can see the plan only has two sections that are long enough to accommodate #5 cross-over switches. I then wanted to create a 'view' block between the yard and the the Han2/Han3 crossover. I opted for a partial, low profile, view block by using an elevated Main Street scene. This allows you to see most of the layout while standing in the aisle  next to the trestle and  effectively providing a view block of the yard. The next phase was how to create a stand alone scene with the cross-over. As you can see there is very little room in the space between the yard and the cross-over which necessitated the vertical portions of the view block needed to be nearly completely vertical i.e. either a cliff or a wall. On the yard side of the view block I opted for the wall and to use cliffs  on the other side. So my next thought was to create the gorge and bridge for the scene. This is the original concept sketch the project.

This then began the search for bridge ideas which took countless hours  examining  thousand images of both real and model bridges. I kept coming back the HO/HOn3 Micro Engineering tall steel viaduct as the look I was hoping to achieve. I was not able to find anything available in O scale that would work to build the trestle. The breakthrough came when Steve Ross brought his deck girder bridges to market. They are beautiful pieces and being made in varying lengths it allowed me  to mix and match to get the correct length. At this time Steve had not produced either the shortened narrow deck spans where the trestle bents should support the bridge, nor had he produced the trestle bents themselves. So I added the deck girder bridges under the track and supported them with 1X3 boards while I worked on figuring out the trestle bents. In my searches I had found an image from Main Line Bridges that I thought would work.

The next challenge was to build the trestle piers and it was while thumbing through the Plastruct catalog that the epiphany of construction them by gluing up I beams and Warren truss bridge supports came. Once the trestle piers were built the remainder of the construction followed suit. The only fiddley bit was getting the 'canted in' angle of each of the towers to be square, level  and match one another. Once the box girder trestle supports were built they needed to be fitted under the bridge deck. The concrete bridge piers are glued up 1X3 s cut to proper shape and then painted. The next few images are added only for context. The first is an overhead of the bridge showing some of the interior/underside detail of the Ross bridge decks an how nicely the track fits onto the deck.

The last two are earlier images showing some of the scenery construction.

Well i guess the word is out I'm not a civil engineer, but in all seriousness I want to truly thank every one for their kind words. I hope this provides some insight as to how I approached this project. There is still much to do. Frankly I'm intimidated to add in the water in spite of having three rivers on the layout. I'm worried I'll end up with big glob of resin and doesn't look good. Steve I wish you success in your project, keep the fourm updated on your progress.

Mike

These are the missing images, not sure what happened

I'll post this and see if it comes through, Mike

Thanks, I will read through it later today.