I've become a little bridge obsessed.  This bridge rail is inspired by the famous Sydney Harbour Bridge in Sydney. 

When you look at the 3MF file you'll see 4 plates:

01 - Arch Bridge 2 Hx - this is a 2Hx version.

02 - Arch Bridge 3 Hx - this is a 3Hx version.

03 -  Arch Bridge 4 Hx - This is a 4Hx version.

04 - All - this plate has all the rails on a single plate.

Note: that I've used supports on the rail prongs and under the middlemost spans of the bigger rails.  These rails print flat so a brim is unnecessary. Here's a new video demonstrating the rails.