Bridge construction

[Anonymous]

I have a place on my layout that needs a double track bridge to span about 4 feet.

I would like to build it myself as I have never seen any kits even close to that size.

Any suggestions for design or links?

[fiatfan]

Central Valley and Campbell both make some nice bridge kits. Perhaps you could combine two or three to make one long bridge.

Tom

[twhite]

How deep a canyon or ravine or river does it have to cross? Since you said double track, Walther's makes a handsome double-track through truss bridge. Probably 3 of the kits would span the four feet you need. However, it depends on how deep your crossing is--through trusses are not meant to span gorges. If it's a deep gorge, you might take a look at the Microscale tall viaducts, you would need multiple kits, but you could parallel two of them and stagger the bents. And if it's a REALLY deep canyon, take a look at Faller's "Beichstahl" bridge kit in the Walther's catalogue. It's a steel arch double-track bridge that could be 'Americanized' with a little work. And it's about 40" long, so you could work it with some approach spans on either side.
Tom

[Anonymous]

Well, there is a 3 foot span that is going over a walk way. The rest is going over a small yard for my steel mill. I took another look last night - I will probably need closer to 6 feet.

I will look into your suggestions. I wonder if anyone is running any buy 1 kit, get 4 free specials this month...

Thanks -

[tomwatkins]

If you don't already have it, the Kalmbach book on bridges and trestles is excellent. It's got lots of information on why and how the prototypes used certain types of bridges in particular situations and on scratchbuilding and kitbashing model bridges to fit particular needs on layouts.
Have Fun,
Tom Watkins

[cacole]

Miami Valley Products makes a redwood double track bridge kit that is that long. We have one on the Cochise & Western Model Railroad Club's HO scale layout. The only problem with this company is their very slow service. I think it is a one-man operation who puts the kits together only after several orders come in.

[ndbprr]

I had a five foot bridge spanning a duckunder one time. I made it from a 2 x 8. I cut both sides square on a table saw and built up the sides like a girder bridge with Plastruct shapes. Nobody ever commented thatit spanned that distance without any support piers.

[Anonymous]

QUOTE: Originally posted by ndbprr

I had a five foot bridge spanning a duckunder one time. I made it from a 2 x 8. I cut both sides square on a table saw and built up the sides like a girder bridge with Plastruct shapes. Nobody ever commented thatit spanned that distance without any support piers.

I was thinking along that line - that may not be a bad idea. I like the idea of combining the kits too, but I can see the $ adding up...

-Chris

[Anonymous]

You said you need to span over a yard next to your steel mill and then clear a three feet walkway and that you believe the overall length will need to be about six feet. I am curious how high this track will be over the steel mill complex?

To make it cheap, I would want to make it appear to be a steel plate (deck) girder viaduct, but that won't get you over the steel mill unless my mental picture of your mill is mixed up. "ndbprr" alluded to my recommendation. I would rip both sides off a 2x4 making a piece of wood a little less than 2.75 inches wide. Then you need to paint it flat black. After that, get some 50' girder four packs sold by MEI. Glue the bottom flange cover plates on the girders and paint them the color of your typical RR girder bridge (I use an aluminum color). Next, glue these girders to both sides of the 2x2.75 so the top flange is just barely above the top surface of the wood. Then get some Plastruct sheet and cut strips the same width as the top flange from the sheet (about sixteen scale inches wide). Cut these strips to match the length of the girder flange (about fifty scale feet) and paint them the same color as the girders. Glue these strips to the top of the wood about 3/4 inch from each outside face of your wood (about 1.25 inches apart centered along the wood) These strips represent the top flange of the other girders paired with the two outside girders. Beneath the bottom, you will need to mimic the bottom flange as well, if this side is visible. Now, I would buy MEI bridge flextrack [code 83] (but it isn' t cheap) and lay that over the flanges as the double track. Buy some Code 70 or code 55 rail and lay that inside as guardrail. Then build the refuges about every two or three feet on both sides. This is a cheap way to construct a fairly long steel plate girder viaduct for HO Scale. Instead of the MEI flextrack, you may want to scratchbuild the track along the bridge because I think track in this circumstance is constructed of a single tie under all rails.

To get over the steel mill area, you may want to consider either a single span deck truss or thru truss depending on the clearence from the bridge track to the ground beneath. I would scratch build a truss for this using Plastruct shapes. I also want to recommend you inquire about some products available from a company called Three Brothers Manufacturing, Inc. They offer something called Bridgemaster Series Rivit Detail Sheet #4000. My address for this company is 3555 E. Layton Ave. Cudahy, WI 53110 -or- www.threebrothersmfg.com

Good Luck. - Ed

[Anonymous]

Wow - thanks for the detailed reply. That info is EXACTLY what I was looking for. I will have to read it a few times to assemble it in my head. (you don't happen to have any sketches or section views you could email me?)

Oh - I only need to clear track, no structures (I was not clear on that earlier). The bridge will pass between some structures by the steel mill, but not over, so the elevation only needs to be around 3 inches or so over the entire span.