In the tall corner of the room, the trestle bents came together for a broad curve. This is the one broad G-scale curve in the layout. The large curve (70" diameter) fills a dormer window. The trestle bents are G-scale as are the metal bridges semi-circle bridges. The tall, light-coloured wooden columns were inherited with the house purchase. They were meant to hold up a fancy front door entrance porch but when you take the tops off and cut them to fit the correct heights.
Just for perspective this is my arm fully raised above my head.
In a semi-panorama view, the 16' span is on the left and Bridge One on the right. The curve looks somewhat square in this view but it is a long gentle 180.
These metal bridge curves from a Facebook Alabama Marketplace purchase, are meant for outside use and where they can be supported by concrete so they are very heavy. As you can see below, very conveniently they came well rusted aka "weathered" so they look old and worn, just the way steam railroad assets should look. None of these things was meant to work together so a lot of creativity was needed to keep the trestle bents and spans.
Then we needed to fabricate a long curved thin hardboard platform to support the HO-scale track.
Lots of clamps and lots of weight to glue down the platform.
This is a European cog (aka rack and pinion) steam locomotive work train is making the first run on the new rail section. I agree it is rather an elegant locomotive for a work train.
Another HO-scale Fleischmann passenger train traversing the rusty old G-scale steel bridge.