Deck Plate Girder Bridge - Removable Deck Plate Girder Bridge
04/04/2012
The purpose of this bridge is to connect a removable module in the room's closet to my main layout. The span is just shy of two feet (real-world). I wanted it to be solid and straight, so I started off with a 3/4"-thick quality plywood piece cut a bit longer and wider than needed. To make sure the board would stay straight over time, I glued two 1/4"-thick pieces of plywood, one on the bottom and one on the top, to make the board 1-1/8" thick. When this was dry, I cut the board to the right length (fitting it frequently), and made it two inches wide. Using some 1/2"-thick solid oak wood, I cut two supports on top of which the bridge will rest. I glued one block to one side of the support. The other block will be glued in place once the bridge is finished.
Deck Plate Girder Bridge
Next, I glued sections of 0.010" styrene to the bottom and front of the bridge. I used 5-minute epoxy for that. The bottom was probably not that critical, but just in case some short person looked up at the bridge, it wouldn't look like a piece of wood. When that was dry, I glued some scale 4" styrene angles to the front side of the bridge. These represent the girder support angles. This close-up photo shows the end, which I left uncovered. That is because the last 1/2" of the bridge will rest on the supports shown in the previous photo.
Deck Plate Girder Bridge
Although hard to see in this photo, I used Model Master "Gray Primer" in a spray can to paint all of the styrene on the bridge. This worked well, and I like the color as-is.
Deck Plate Girder Bridge
I painted the rest of the exposed wood with a flat black latex paint. This helps seal the wood. The flat black will give the illusion that the bridge is hollow on the inside (like the other two bridges I built, shown on the previous page). I cut a pile of ties using my standard technique for making my own ties. The shorter ties are 12 scale feet long and the longer ones are 18 feet long. I tried to space them about a scale 3 to 4 inches apart, which is what prototype bridges seem to use. I should have started the ties at the very end of the bridge, but I fixed that later on.
Deck Plate Girder Bridge
The ties were stained with Minwax "Special Walnut", which is what I use for all the ties on my layout. I stained all exposed areas of the ties, and tried to make sure I didn't get any stain on the styrene front edge of the bridge.
Deck Plate Girder Bridge
Here's the complete bridge at this stage.
Deck Plate Girder Bridge
Dry-brushing white paint on the ties helps to age them a bit. You can see the difference here when I stopped to take this photo midway.
Deck Plate Girder Bridge
Before installing the rail, I needed to make access holes for the wires that provide electricity to those rails. I drilled a large-diameter hole into the back side of the bridge, in about the center of the bridge. Then I drilled two smaller holes in between two ties down into the large-diameter hole.
Deck Plate Girder Bridge
I soldered the wire to the bottom of the rail, and routed it through the small hole into the larger hole out the back of the bridge. I did the same thing with the other rail's wire. That one was a bit trickier, but with patience I was able to do it.
Deck Plate Girder Bridge
The next step was to spike the rails down. I decided to forego the tie plates on this bridge.
Deck Plate Girder Bridge
The two wires that were soldered to the rails were now connected two wires that run parallel to the back of the bridge. These will connect to the DCC bus wires of the main layout, and provide the through-put connection to the module in the closet. To keep the bridge removable, I decided to use 1/8" mono phone plugs and jacks.
Deck Plate Girder Bridge
The plugs were soldered to the wires. The center tip is connected to the red wire. The jacks will be installed in the layout.
Deck Plate Girder Bridge
For the main rails I use code 83 on my layout. I would have chosen code 70 for the bridge rails. However, I didn't have enough on hand, so I used code 55 rail for the bridge rails (left over from my N-scale days). I used superglue to attach the bridges rails to the ties. This photo shows the bridge from the layout's side facing the closet.
Deck Plate Girder Bridge
I found that the dangling wires in the back got in the way, so I fastened them to the back of the bridge, while still making it possible to twist the wires enough to plug the plug into the jacks.
Deck Plate Girder Bridge
I used Bragdon Enterprises' weathering chalks to weather the center of the track after the rails were painted with Floquil's "Rail Brown". I only painted the rail portions that are visible from the front of the layout.
Deck Plate Girder Bridge
I wanted to add a handrail to the bridge for a very practical reason; the bridge is actually up almost 50" from the ground, so a derailed car or engine could wind up on the floor. At first I thought about making one from strip wood, but I have already done one like that. I wanted to challenge myself and try something I had never done before. I decided to make the whole handrail out of 0.025" phosphor bronze wire. I cut several scale 6-foot long pieces, drilled holes in the longer ties, and used superglue to glue them into the holes. I tried to hand-drill as straight as possible; most came out well... (update: I installed the handrails too close to the track; they need to be moved out farther should you follow these directions, because they only leave about a scale 6 inches of clearance for the cars and engines - which I discovered a bit too late!).
Deck Plate Girder Bridge
I had previously bought a package of 3-foot long lengths of this brass wire, so I could now use that to make the horizontal members of the handrail using one single piece. I put a strip of Plastruct ABS H-column (on its side) on top of the ties, lightly clamped that down with some miniature clamps, rested the wire on top of the column, and then proceeded soldering the horizontal brass wire to the vertical posts. The next photo shows a tank car being used to make sure that I have left enough clearance between the car the handrails (update: use the widest car/engine you have; not the one closest to you when testing!).
Deck Plate Girder Bridge
This photo shows the top horizontal rail being installed. It also shows the H-column to keep the rails about two scale feet apart. It helped keep them fairly straight and even along the length of the bridge.
Deck Plate Girder Bridge
I installed a handful of angled pieces on the outside of the handrails to act as braces. The soldered handrail itself was very strong, but I put these in there to be a bit more prototypically accurate. I'm getting ready to paint the handrail with Floquil's "Primer".
Deck Plate Girder Bridge
After I painted the handrails, I cut a pile of 5"x6" scale strip wood for the walking boards on either side of the track. I used that size because I had a lot of it available and it is such an odd size that it probably won't be used in any structures I'm going to build. I cut the boards at random lengths, so that the joints between them are staggered and look more haphazard. I like the way that came out. Next I stained them with the same stain I mentioned above. When I took this photo I was busy dry-brushing while paint on the new walk boards to age them a bit. Once I finish the front half, the bridge is complete.
Deck Plate Girder Bridge
Update: I tried to live with the handrails being too close to the equipment on the bridge, but there were several cars that hit them, so I bit the bullet and cut them off. I decided to build new handrails. It went much faster the second time around. However, I ran out of 0.025" wire, so I changed the design of the handrails a bit. I moved them about 3 scale feet further away from the track (on each side). After painting the handrails, I put more walkway boards down and stained and weathered them as before. The photo below is of the revised and completed model. It took me about two weeks of modeling time to build this bridge, and several days to re-do the handrails. It was a fun project.
Deck Plate Girder Bridge