Those of you who know me are aware that I have a modular layout that is strictly subway. In the future I may move and modify the layout, hopefully integrating most of my modules into a new layout. Nothing is definite, but the current obstruction, room snaking 14x51 layout running a single train would change to a non obstructed 15x40 layout running 5 simultaneous trains. That new layout would include a nice elevated structure consisting of over 200 track girders which means over 100 girder bridges for the tracks alone. There would also be a 4% grade subway to elevated ramp. So I have decided to prepare for that possibility.
The attached photos show a completed girder bridge based on the Dual Contracts design of 1915. To be fair I must also credit Steve Olsen of the NYC Model Transit Association who posted a great guide on elevated subway building back in 2002. My design differs from his in 4 ways:
1. My girder bridge is 50 scale feet versus Steve's being 48 scale feet.
2. Unlike Steve's design where he fits the width of the web of track girder with 11 angle pieces on one side, my design fits the web on both sides. (Steve am I correct about the one side?)
3. With the exception of the sills and attachments in the cross bracing, ABS plastic is used instead of styrene.
4. The thickness of the web of the track girder in my design is .030 inch versus the .020 inch in Steve's design.
I have estimated that the total parts cost per girder bridge is about $15 and takes roughly 6 hours of my time.
The parts are all Plastruct:
#90366 - ABS strip .030 x 1.25 (web of track girder)
#90003 - ABS 3/32 inch angles (bracing the width of the track girder and the cross bracing)
#90739 - Styrene strip .030 x .250 (sills of the track girder and cross bracing support)
#90728 - Styrene strip .020 x .187 (cross bracing support)