I had a few bridges on this first layout of mine,...the Atlas Plan 'Central Midland"
That single mainline bridge that was one of the first structures I built from a
Plastruct kit, and I did much of it by candlelight as that was the winter we lost power at the house for 5 days due to a severe winter ice storm...ha...ha.)
Obviously I like bridges on my layout. Did you count the number I have there?....and only two of them are the same....the 2 modified Atlas Curved-Cord bridges.
6 bridges total
FAKE BRIDGES
Several of my bridges were not really bridges in the truest sense,.... they didn't have their bottom structures.
Both of these were the double-track bridges that I kit-bashed from single-track Atlas/Roco Curved Cord Bridge kits. I simply took two single track bridge kits and 'doubled' the upper connecting beam structure to effectively provide for a dbl track spacing between the curved cord beam structures.
I left the bottoms out (to be used on other projects*), and just relied on the roadbed to provide support for the track of the bridge. I glued four 'locating pins' onto the corners of the curved cord sides, and these plugged into 4 holes drilled into the plywood roadbed. This kept the 'bridge' properly located, and its side frames properly spaced apart such as to not interfere with the passing trains.
One of these dbl track bridges was set up as a safety device,....that one against the backside of the layout right at the point of the crossover switching between the 2 mainlines. I had in the past experienced several of my nice steam engines derailing and crashing off the layout onto the concrete floor...NOT a pleasant experience!! I decided I was going to put up this bridge structure to prevent any derailed loco from experiencing that fall off the side. Strange as it might seem, after I put this 'guard-rail bridge' into place. I hardly ever experienced any other derailments ??
That 'fake bridge' precipitated the idea of a stream/river running under it and out into the 'country backdrop'. It also meant I have to have another bridge for the inner track,....thus the 'deckbridge' to allow for variety.
The other 'fake bridge' came about as a result of my adding the Walther's double track truss bridge for the dual tracks I wanted to have enter into the turntable zone. Since I had that bridge actually spanning the lower tracks, its only naturally the my yard entrance tracks would also be spanning those mainlines below. The 'fake double chord bridge' was the easiest way to do this without tearing out the subroadbed and replacing it with an actual real bridge. Besides with all the ballast, and cinders, etc in this yard area, no one would ever tell there was no bottom on that bridge. I also had to pay particular attention to the exact location of those bridge side frames so as to not interfere with the swinging passenger cars and articulated Big Boy loco that would come thru that trackage.