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Polyjim, I live in Richmond VA, home of the RF&P which is now owned by CSX. As a result, I model the two big Easterns, CSX and NS. I had a layout in our extra bedroom with track and wiring complete for two mainline cabs and one in the yard but no sceanery, just a few buildings. When my son came along, I dismantled it and put it in the attic but it was designed with that in mind so it wasn't the end of the world. Now I am working on a '4 x 8' for my son which is hinged in the middle so we can put it away when we are not using it. All track is Atlas, code 100. I have built a few model bridges which I keep in my office. I design bridges for a living and my models help me describe various construction problems to the new engineers and sometimes the managers too. I am blessed to have a job I enjoy (most of the time) and that is why I don't mind helping y'all out with your bridge questiions on the forum. Something I should have asked earlier . . . Is this bridge on a tangent (straight) or will a portion of it need to be in a curve? I assumed it would all be straight when you asked about building a suspension bridge but I should have made sure before. How long of a tangent can you allow for the bridge? I also hope that it will be single or double track over its full length. You said you had a piece of 36 inch flex track where the bridge will be built. While you are waiting for the completed structure, I would put a 1 x 4 board there and glue some MEI 50' bridge girders to the near side to conceal the 1 x 4. After the bridge is finished, you could use the 50' girders for other bridges on the layout. MEI (Micro Engineering Inc) sells a bag of four 50' girders for less than ten bucks. It looks like the 'false bridge' approach for your duckunder is acceptable. Great. Now we need to agree on the span arrangement. Central Valley sells a 150 ft through truss (single track) kit, and a 72 ft through girder (single track) kit. MEI sells 50 ft through girder bridges, either single or double track, 50 ft deck girder kits and 30 ft deck girder kits. They also permit open or ballasted decks on their kits by using a piece of grey plastic to simulate the deck. There are other kits by Walthers but I like the MEI and Central Valley kits. For sceanic intrest I would recommend either: 72 ft - 150 ft - 72 ft span arrangement (40.5" long) 50 ft - 150 ft - 50 ft span arrangement (34.4" long) 72 ft - 150 ft span arrangement (30.6" long) 50 ft - 150 ft span arrangement (27.6" long) 50 ft - 72 ft - 50 ft span arrangement (23.7" long) 30 ft - 72 ft - 72 ft - 30 ft span arrangement (28.1" long) The best options are the ones with 150 ft main spans because that is where the 'channel' would be for the stream below. You would want to show a stream and flood plains on either side. The stream bed may be dry or not, but there should be a well defined 'channel' under the main span. I'll be more specific after we get a little further with the concept. I gotta go play some golf. I'll catch you later. Ed
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