I'll build steel double track truss bridge..... design done! G scale

I think it looks good, but kinda long for the footings. I think it needs a pier in the center. I don't think change of size would change that look. The good news is a pebble (stone) pier would look good there IMO. Use a full mask, wear a hat to keep debris from entering up higb after they bounce off your forhead. Debris getting between glasses/mask & your face are just as dangerous as they keep debris from traveling away from eyes. Grinders as cutters mean locking the piece down well too. My worst tool incidents were nearly all grider related. From new front teeth and stitches to countless trips to the eye doctor. (Many because I was wearing saftey glasses and they funneled debris into my eyes vs "saving them", but flying splinters and exploding discs still demand it. Better a scraping than an eye surgery. Light, tight cloths. (I've had a tie get grabbed by a drill, and a sleeve ripped off at the seems by a printing press after a cuff button popped and the sleave dropped into the ink rollers. My shoulder was black and blue....even after the ink was cleaned off it. Scary) Maybe better yet, they have this stuff called "sunblock" available at stores

Here's a page with diagrams of real truss bridges. I like the Pennsylvania and Parker style, with the arched top, myself.

https://www.arkansashighways.c...rd_bridge_plans.aspx

nickaix posted:

Here's a page with diagrams of real truss bridges. I like the Pennsylvania and Parker style, with the arched top, myself.

https://www.arkansashighways.c...rd_bridge_plans.aspx

WOW! Thanks!

I found this one on bridge hunter site. I can't tell the full dimensions. You can view by RR. I'll keep comparing. I found one last year and it must have got deleted.

I know that in St. Louis there are three similar truss bridges crossing the Mississippi: Merchants, McKinley, and MacArthur. I believe all three are Pennsylvania truss. Each of them has three spans, and each span is over 500' long (over 600' on the MacArthur). I think the McKinley is the most elegant of the three, though no longer a railroad bridge.

Courtesy of Bridgehunter:

http://bridgehunter.com/photos/35/69/356935-L.jpg

This dead-on shot of a single span may be helpful!

http://bridgehunter.com/photos/35/69/356939-L.jpg

nickaix posted:

Here's a page with diagrams of real truss bridges. I like the Pennsylvania and Parker style, with the arched top, myself.

https://www.arkansashighways.c...rd_bridge_plans.aspx

Thanks for posting this is a source of great information

It's pretty simple but I'm leaning towards this now (on bridge hunter site). Looks like less welding.

Are you building a G or O gauge bridge?

The Atlas pratt truss bridge in O gauge with the double track expansion kit is an excellent O gauge bridge.  The bridge deck is UV plastic just like the Atlas track.  The bridge can be protected from sunlight by painting it.  The Atlas bridge is 40 inches long and comes in both a 2 and 3 rail version.  I know of several that been installed on O gauge garden railroads that have outside for about 3 years without any issues.  You might be able to modify an Atlas truss for G gauge.  NH Joe

Well I'm moving forwards. If it doesn't end up perfect, I'll  deal with it.

It's done. I could have made more diagonal braces. They are just for looks here. There just isn't the forces involved in a scale bridge of this size. I'm happy anyways. We'll see how long it holds up.

The bridge is now open for train traffic!

Great thread, excellent result. I was betting you would go with a flat truss. That arc looks complicated!

Very nice work!  This is a great project, thanks for sharing.

  I gotta admit, I wasn't expecting an arch either; bravo Joe.

 

  I'm also curious about your welds, flux or gas atmosphere and previous experience or how you're learning/type of welder your learning from. (I really enjoyed learning to mig weld, and did so from folks in various niches of the trade, pipe only, aluminum, stainless, heavy industrial, etc.. My buddy that taught me stainless has pieces in a few schools used as examples.  Always good, he got really good watching robot welding. It allowed him to watch the color changes in the beads closer. When you get past basics, if you move to a lighter lens for a few tries, you'll see varying shades of bright-red to med-red to red-black; which is heat spreading and contaminate working it's way out. Going back to dark lens well before you get itchy eye (weld flash) you'll know what else to look for. It's just hard to notice at first with a #12 lens

  If you did it right, the metal stock will give out before a weld does.

If you only did o.k. you're still likely never gonna have issue unless maybe you try to cross over it on the riding mower or something equally brilliant😂 

What's next? A yard crane?😯

I was thinking of lighting up the bridge. I didn't know how to get the lights strung up onto the bridge so that it wouldn't look too bad. I chose instead to just blast the thing with flood lights for now. I still have to finish the water fall area and decide to make these lights more permanent or replace them.

Wow, very nice!

CONGRATS on an EXCELLENT job! ☺

Joe, although pictures don't always give the best idea, I think the lights as is look really good.  Once water is running I think you'll get some good shadow and reflection effects.  Sometimes less is more.