The Railroad Bridge
Something of a minor masterpiece, the railroad bridge is the third iteration of a series of bridges at Martini Junction. The very first bridge was a gifted wooden Arch Bridge dating back to the turn of the century: ie "this century". It didn't stand up too well and was eventually replaced by another bridge of the same design, but constructed using square plastic tubing used in model making. This worked for a while though it required frequent patching up and that led to the search for a more substantial material.
A breakthrough came when I read about a guy who was using screen framing stock for bridge building. The size was perfect, being rectangular and measuring 5/16 x 5/8 and looking very much like a steel beam at the scale I was working in, that being 1/24 or so and readily available at Home Depot. The guy in the story was using small screws and nuts to hold things together but I had a lot of experience working with pop rivets and decided that 3/32 dia. rivets would work just fine.
This new bridge would take the form of a Thru Truss Bridge. A framing jig was made and work began in earnest. Gusset plates, using .020 thick aluminum sheets, were used to hold things together and resulted in a pretty sturdy structure. I popped a lot of rivets but was happy enough with the final result that I built a second half-bridge which serves as a mantelpiece over the fireplace and of course another train. And when we were contemplating the dismantling of the railway and I brought the bridge home to use in the backyard, I decided to make yet another bridge to put back out at the Junction. That's and grand total of three and one-half (3 1/2) bridges. I'm done.
Original Wooden Arch
The magnificent Thru Truss Bridge