3 1/2 X5 N scale layout. Need to install bridges over (proposed) rivers. But the track over the river is curved.
Straight track would send the line off the board. Has anyone ever bought/built/kitbashed a curved bridge?
Thanks. Sid
Generally, in this day in age the tracks are curved, but the bridge is not. That is to say a wider bridge, say a two track bridge is used with a single track on it, and the straight bridge sections are supported by their piers, but the track runs its nice gentle curve across the bridge.
Yes of course there are 1:1 curved bridges, but these are trestles rather than bridges. Bridges be they steel structure or suspension bridges like to be in straight sections,
If I had to build a curved bridge in HO, I would lay the track on a plywood support so that it is solid and located exactly where I wanted it, and then I would build the bridge structure around it, either in straight segments as I have suggested or with trestles underneath the tracks.
Such are my thoughts, your bridges may work differently.
ROAR
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You'll need to first choose the bridge style best-suited to your situation. I used Micro Engineering bridge kits to make these in HO scale:
This one also uses some Atlas deck bridges:
Micro Engineering
Wayne
This is a curved trestle on my layout.
It's built in straight sections that meet at an angle atop each support. I used Micro Engineering deck girder bridges and scratchbuilt the rest from styrene and Central Valley parts. This is HO, but there are similar components you could use in N.
The bottom track curves across a scratchbuilt culvert. The culvert is straight, but wide enough for fill and ballast on top. I've seen larger culverts and bridges that use the same idea.
Rob Spangler
This is a curved timber trestle on my last layout, but really only the rails and guard rails are curved. The stringers supporting the ties under the rails are arranged so that they can support curved rails. However, the outboard stringers that you see reaching beween the bent frames are not curved, obviously. They are angled, though, and you should be able to see how that looks with the full-sized image (click on it).
Here is a real-world example in modern times.
Crandell
A 'curved' bridge (with one notable exception) is actually a series of short straight bridges that support curved rails. Even wood trestles have straight main beams under the ties - they meet on the caps of the bents at an angle.
I have a very nice poster of a multiple deck girder bridge on a curve about three meters from my right shoulder. The girders are straight, but the rails aren't. It's also on a pretty severe grade, judging by the fact that the triple-headed D51 class 2-8-2s are working hard and filling the air with greyish steam.
As for the exception - try a masonry arch. The edge outside of the curve will be straight from one abutment to the other, but the edge on the inside of the curve can be curved to match the track supported. Of course, they are always closed-deck structures. I have a nice concrete spandrel arch on a curve in my future, modeled on a prototype near the Okutama station at the end of the O-me -sen in Tokyo.
Chuck (Modeling Central Japan in September, 1964)
The Ybbstalbahn (Ybbs Valley Railway), a narrow gauge line in Austria, has a curved steel trestle bridge.
Gidday Sid, Here's a link to a similar previous thread.
http://cs.trains.com/mrr/f/88/t/170472.aspx
Hope it helps.
Cheers, the Bear
"One difference between pessimists and optimists is that while pessimists are more often right, optimists have far more fun."
VERY Helpful. Thanks.
Sid
selector Here is a real-world example in modern times. Crandell
Selector--I think you forgot to link to the modern image, which is a worthwhile example. I remember it well, as I thought it was part of your layout and has been inspirational to me!
Rick Krall
Yes I have built a curved arch bridge. It was actually straight for about half it's length and curved for the other half - a total of about 2 feet. It was designed for the radius of the inner track to be 36" and the outer track 39". The layout was S scale.
I laminated several pieces of 1x4" pine boards together, drew the curve on the bridge top and the curved arches on the sides. I then cut the curves on my bandsaw. I cut it so the arch openings were parallel to each other and the planned river underneath. I installed the bridge and laid track over it, but never got to adding the "masonry" to it before the layout was torn down due to a move.
I was very pleased with the result even though I never did finish it. My interests have taken a different direction and no masonry bridges are planned for my current under construction layout.
Good luck
Paul
Don't know what prototypical appearance you are looking for, but curved viaduct sections are available in N scale Kato Unitrack, with both single and double tracks. They are basically the standard balasted Unitrack sections fastened to curved plastic bridge girder sections. Unitrack also has adapter pieces to mate up with standard Atlas code 80 sectional or flex track.
Andy
Sid,
I asked once about curved bridges, as I had a track that was curved going over what I wanted to be a creek or stream.
It was suggested on here that I invert a curved section of preformed-premade track with roadbed of the same radii and use that...IF your curve is standard curve radius. I assume for a layout that small you might have a standard curve radius.
I painted it and it come out nice.
Simple, but effective.
-G .
Just my thoughts, ideas, opinions and experiences. Others may vary.
HO and N Scale.
After long and careful thought, they have convinced me. I have come to the conclusion that they are right. The aliens did it.
galaxy Sid, I asked once about curved bridges, as I had a track that was curved going over what I wanted to be a creek or stream. It was suggested on here that I invert a curved section of preformed-premade track with roadbed of the same radii and use that...IF your curve is standard curve radius. I assume for a layout that small you might have a standard curve radius. I painted it and it come out nice. Simple, but effective.
I actually find it far easier to cut a cardstock template of the curved track to tie width, This will allow placement and marking sections of your girders/ beams to find the lenth and will provide you with the fit "miters" of the beams (or deck sections). Pending how tight a radius, use care in selecting the length of the beams to the supports. You don't want extreme tie overhangs on some of the very tight radius. I used a1/4" ply for the template. This allowed me to use the cut away piece (beyond ties) to use for bending the ME bridge flex to a perfect sweeping bend w/o having any kinking. This one pictured was a bit critical as he track starts straight and "eases" into a super elevated 40" radius.
Modeling B&O- Chessie Bob K. www.ssmrc.org