Afternoon all, I am re-building the shelf layout version of my CBAM&J RR and have made a change that brings me to my first effort in N gauge. I picked all this up in an estate sale and can think of no reason not to use it for this layout but it sure is small when I have always run HO and G railroads. Anyway the layout runs around the walls of my office space and is above the door. I have a shelf section there but think it would be more interesting to replace that with a bridge. The length is about 45" so I can either replace the whole section or just work a bridge into part of it. My preference is for a bridge the entire length. Is something like that available either pre built or as a kit or some kind of plans that can be adapted to these dimensions? Thanks for any leads. Rick H.
Depends upon the type of bridge you want. One option is to use several of the Atlas stone viaduct kits. They can be assembled end-to-end to make up whatever length you need. http://shop.atlasrr.com/p-1097-n-viaduct-kit.aspx
45 inches is a long span of track to be unsupported, so we would need more info on exactly what it is you are thinking. Also, what track is in use for the rest of the layout? Many (most) of the bridge kits or pre-made bridges are not much more than a foot long (or ~120-150 scale feet). You can, of course, string 4 together. Examples would include the Kato bridges (truss - 9.75" or girder 7.3"); all the way to the 200' and 320' Micro Engineering viaduct bridges. Or you can even create a wooden trestle across the span (again, with a supporting base). The key to any, though, is how you support them.
Here someone has used 3 Kato bridges to span a 29 inch gap. You would need about 4-5 to cover your distance. Quite a stretch! You would definitely need extra support below.
Rick, I kit bashed 5 Walthers N Scale double track truss bridge kits to make this 45" bridge. The amazing thing is trains actually run over it without falling off! Tim
I found this guy on ebay: http://www.ebay.com/sch/tonetile/m....YEsAAOSwYIxX2wNP&rt=nc&_trksid=p2047675.l2562 Its expensive but appears to be good quality. Once I have the room for a layout I will probably buy one of his.
The 'top end' of N single-span bridges has to be at least close to Bob Knight's Traincat Canyon Diablo bridge - 544 N scale feet on a single arch cantilever works out to a 40 3/4" total span. Bob had announced it, I was certainly looking at it, but the reality of what that cost to produce in etched brass and sell will take your breath away - $1950. I talked with Bob about that at length, and well, it is what it is. I didn't have a used car to trade for it. I still want to build it but can neither fit or afford it. Look at it this way - the top end on railroad bridges - Hurricane Gulch on the Alaska, still only has a 384' middle span (about 30") in N. http://www.alaskarails.org/pix/bridges/AMHA-hurricane-gulch.html . Whirlpool Rapids bridge at Niagara falls (which replaced a suspension bridge) has a clear center span of around 549 feet, again, 40" more or less and a major, major model build. One of my favorites, Youngs High Bridge near Lexington (you can bungee jump off of it now) has a 551' foot clear span in the middle - and is the scariest looking bridge I've ever seen in my life as it was never upgraded from original 1800's pin-connected construction. http://bridgehunter.com/ky/anderson/bh36662/ Unless you've got a prototype to justify such a mammoth single-span in N, you can put a plywood deck as the span and build a multiple-span bridge on top of it, can still be reasonably thin, tough, and affordable. I'm doing a 36" span between T-trak tables using three Central Valley #1810 though truss bridges (150 feet each, almost a foot long) compared to a prototype 4-span bridge that was 641 feet across the Allegheny River - just over 4 N feet, and not really unusual in design at all. I'm putting it on a 3/4 " plywood base 8 x 36" that's modular in design with about a 2" pier elevation above the riverbed (plywood deck). That 8" wide deck will protect it from damage, too. http://www.cvmw.com/nscale.htm I looked at a lot of ideas for truss bridges to get across that 3' span, some were just wrong, some were too modern, some were too expensive or unavailable. I'm surprised more people don't use the Central Valley trusses, they are far more affordable, lots of detail, and you can make a darn big span out of a batch of them. And they sell the parts, too, so if you want to roll your own you can. Those Ebay bridges really don't do it for me, too weird looking. Give me a through truss or a deck truss or a through girder any day, typical design just like a railroad would do unless there's a honkin' canyon down there like Canyon Diablo to justify a single span design with an arch or suspension. Even if you do build it, unless you've got a clear span of 7' or so above the floor, you'll potentially run into it, or have to lower it, or something that will likely damage it.
Tomix/Tomytec makes a double track bridge that spans 22 inches. Two of them would total 44 inches. Bear in mind a 45 inch bridge will have a prototype span of 600 feet. That is a long span for a railroad bridge. Google Tomytec curved cord bridge to find where to obtain them. There was a thread here on Trainboard about them: http://trainboard.com/highball/index.php?threads/tomix-double-track-truss-bridge.77228/
This is a shelf layout and doesn't need to be as accurate as some other projects. It's largely just for fun. I have been laying track on other parts of it and am surprised at how small all this track feels in my hands. It's very different. I'm going to try and design something realistic for this bridge and try to keep it simple. Lots of good help here and I appreciate it. I'll post photos of what I come up with. Rick H.
