curved girder bridges?

Wish I had an answer for this one... so many things you could do with several sizes of curved girder bridge.  Enough to fit a quarter circle of O36 would do nicely.  I've needed this for several projects, but ended up working it out of the design because all the custom solutions I found looked amateurish--and they were still better than what I could have come up with.

Could also use a curved girder to protect against or manage derailments on tight curves.  O27 curved girder would likely have saved many locomotives from cement floors over the last hundred years.

Garrett76,

Check out the website at bridgeboss.com.

Jim is a regular contributor on the OGR Forum.

If he doesn't have what you need he can probably make it.

I have bought several of his products in the past and they work and look great.

Good luck.

and right here is perzactly what a couple look like   , Jim's   054  and 072,  

real good communicating with you also

in real world they are a series of straight section Having said that I used the side sections from scenic express

girder bridge plate by scenic express

     GARRETT76 I know mine is a lot bigger than you are looking for but I made mine out of 1in. fine chip chip board. I cut the 2 curves out of a sheet glued and screwed them together and sanded the sides evenly. The box beam from Scenic Express is what I used to cover the edges of the trestle after I cut the tapers off the ends of the box beam. I shot some rattle can flat black on it and it works for what I need. Choo Choo Kenny

wsdimenna posted:

in real world they are a series of straight section Having said that I used the side sections from scenic express

 

The reason for using straight sections, is that the steel loses its strength when curved. There are prototypical examples of curved girder and panel bridges, but they require more support posts to keep the bridge from deflecting. Some people criticize hobbyists for using curved steel bridges, but what ever works on ones pike should be of no concern to others, unless one asks for constructive criticism. I love all kinds of bridges.

Don

 

 

 

 

 

There are a couple of curved girder bridges near Vancouver, Washington. Saw them up close on an Amtrak trip to Seattle. I'll look for the photos, but you can see them on Google Earth..

For some ideas, this is the curved, wooden Kiskatinaw road bridge on the Canadian section of the Alaska Highway.

Bob Anderson on this forum made a cool, removable curved girder using Fastrack.  Maybe he will chime in with some photos.

Rick

Firewood posted:

For some ideas, this is the curved, wooden Kiskatinaw road bridge on the Canadian section of the Alaska Highway.

It is difficult to tell from the camera angles, but this bridge appears to be constructed from several straight truss sections that support a curved deck.  This would be standard engineering practice.  The famous Western Pacific Keddie Wye bridge in CA is a classic example of a curved railroad track supported by straight trusses.

Model railroaders build curved truss bridges because our curves are so much sharper than the prototype and because we lack the space for a straight bridge.  Also, the truss on most model railroad bridges does not support the train load.

The G&O's Norris Falls bridge is a classic example of this model railroad construction.  There was only room for an O-72 curve.  The main support is a plywood deck supported by wood trestles.  The "steel trusses" are held to the side of the bridge with double sided tape.  They are there for there appearance not to provide support.

The Norris Falls bridge is very real in one respect.  It does carry the G&O across a real waterfall and must withstand the weather.

Not exactly girder, but...

Made from plywood and plastic molding from Home Depot and wooden bents:

Flat plate girders can be made to follow a curved road bed

Garrett, 

Damian at Main Line Bridges makes beautiful curved girders, along with many other bridge types.   He custom-made me a curved girder to match Standard Gauge 72 radius track.  Spend some time looking around his website, he makes some pretty incredible stuff, and very well made.

david

I followed an example posted by Jim Policastro of the forum. 1/2" plywood base with 1/8" Masonite sides. Balsa strips for ribs and girders  

I worked with Jim Robinson from Bridgeboss who made my curved "girder bridge" using the geometry from the tracks I used. He's great to work with. And then I made the supports based on Jim Policastro's article.

Mike

New Haven Joe posted:

Firewood posted:

For some ideas, this is the curved, wooden Kiskatinaw road bridge on the Canadian section of the Alaska Highway.

It is difficult to tell from the camera angles, but this bridge appears to be constructed from several straight truss sections that support a curved deck.  This would be standard engineering practice.  The famous Western Pacific Keddie Wye bridge in CA is a classic example of a curved railroad track supported by straight trusses.

Correct; there's a small group of wooden trusses and trestle bents in straight sections. The interesting thing is the wooden decking laid with some edge-set in a curve. 

https://dreamstreamr.files.wor...7/p1010530.jpg?w=640

Here are some more photos of the elevated line and alternative supports mentioned by Mike and John above. While curved girder highway bridges exist, I don't believe any railroad bridges are built with curved girders. But, sometimes we have to bend the engineering rules for the sake of practicality on our layouts.

Jim

Garrett76 posted:

Hi, I am wondering if there are curved girder bridges that will fit Fastrack O36.  I'm toying with running a 2 level layout- the lower level track in canyons and the upper track crossing the canyons via girder bridges.  It would be nice to have the flexibility to used curved bridges in addition to straight.  thanks

Hi.

I just now came across this thread relative to curves girder bridges. I also offer curved girders in most all sizes from 027 and up. They are offered in two versions, ribbed type and cutout version. See below a few examples. Thanks for looking.

jim r

jim r

I made girder bridges out of 1" strips of Masonite and blocks of  1x.

I used the formed curve of my Gargraves track to attain the proper curve.

 Holding the strips in place with clamps I screwed and glued two strips together. 

I used a scrap strip to hold the curve while the glue was drying. 

Once dry I attached it to the platform with another piece of 1X.

The span was supported by cutdown discarded beacon towers.

I finished them with girders from scenic express.

The gargraves track was screwed to the spacer blocks.

Might want to take a look at a prototype example....

something that was on the C&B in Curwensville, PA

Garrett:

Are you looking for wood or 'metal' style? The chords on the ones pictured below were laminated.

Joe

It's my understanding that the individual spans are actually straight in 1:1 girder bridges, and that a curved roadway is built on top of them.

MaxSouthOz posted:

It's my understanding that the individual spans are actually straight in 1:1 girder bridges, and that a curved roadway is built on top of them.

Max. You are certainly correct.

However, remember that this is a hobby where all of us create what we desire, and are not necessarily interested in being prototypical.

It would be quite a chore for most of us to make up large curved girder bridges with multiple straight sections.

The ELevated Subway Bridge system I created does offer pretty much what you are referencing, short straight support beams on all curves (and straights).

See below an example.

thanks,

jim r

Hi Jim

I wasn't meaning to be critical; just making an observation, based on the photograph.

I'm the last person to slavishly follow the prototype. 

I do feel however, that where ever it's possible, it does help with the over all look of the model.

Cheers

Max.

 I too was not trying to stir the pot. Just clarifying that we all kinda do our own thing in this great hobby.

jim r