69" HO scale bridge question.

[NCGrimbo]

Hello all. This is my first post to this forum. I'm in the very early process of designing my layout. It's going to be built in my second floor and have a tunnel that leads to the raised ceiling area of my first floor living room. I will be having the tracks circle the living room with the tunnel I mentioned earlier on one wall and another tunnel on the opposite wall that leads to the second part of the second floor layout. In the living room, the track will circle the whole room, all 4 walls. One wall of the living room connects to a hallway to the front door of my house and this hallway has the same ceiling height as the living room. This means that I will need to build a bridge across the hall to make the track continuous throughout the entire room. The gap is 69". Can anyone point me in the direction of a good tutorial on building a bridge that will span this gap without flexing? I'm planning on anchoring the left and right edge of the bridge supports to the walls of the living room right where the hall's corner is and on the opposite wall of the hall. This means part of the bridge will be curved, which is causing me problems.

Thanks!
NC Grimbo

 

[LongIslandTom]

When I lived in Buffalo, NY for four years, I always food-shopped at a supermarket that had a G-scale train running on tracks they suspended from the ceiling above the checkout lines using thick-gauge wire (similar to how one hangs the lattice for suspended ceiling panels).

Maybe you can do the same-- Suspend say a through-truss bridge from your ceiling using piano wires or something. The small diameter of piano wires should make it minimally visible.

 

[pgandw]

If you can't suspend from the ceiling or cantilever off the wall, then you are going to need a rigid structure that won't sag over 69", and preferably light as well. The curved part makes things a lot more difficult.

If this is your case I would cut a base and top for a curved box beam out of at least 1/2" plywood. Use 1/4" plywood for about 3" deep sides (assumes 1/4" ply will bend to your required curve). Glue a 2" thick piece to bottom and both sides, and glue sides to bottom. Finally glue top on to foam and sides. Result will be very strong, and reasonably light to lift off if needed. Paint the sides to look something like a bridge.

my thoughts, your choices

 

[RonP]

I would go arched suspension bridge, with a nice and strong (could be heavy) arch you can build the rest light with wire or fishing line dropping to your road bed. I am a stair builder so i'd use 3/16 inch strips of poplar (easy to paint) formed/glued into your arch and tied from end to end like a bow. The rest of the plans should be simple to find.

 

[shaygetz]

I would go arched suspension bridge,

That reminds me of an article in an early to mid 90s Model Railroader magazine featuring a layout that sported an arch bridge over 9 feet high and over 12 feet long made up of girder like stainless steel used in window construction, silver-soldered together. We have a local restaurant called Granny Cantrell's that has 7 G scale layouts suspended from the ceiling on these beautiful latticework girders that have to be commercially available.

 

[NCGrimbo]

Thanks for the replies. I like the idea of a suspension bridge. Any links to plans to get me started?

Thanks again.