Wednesday, January 7, 2015

County Bridge Under Construction

This photograph was taken in 1888 when the bridge was five years old. This view looks south across the river into Oakdale. Enough detail could be obtained from this view to reasonably scale the model.
In 1883, the supervisors of Stanislaus County decided to spend $14,739 for a new iron bridge across the Stanislaus River just north of Oakdale. It was a spindly structure but apparently carried wagon, then auto traffic across the river well into the 20th century. Since the bridge is just upstream from the S&C railroad bridge, I felt that it had to be included in my model.
With the piers in place, the river valley can now be scenicked. The road runs along the top of the right-hand hill toward the bridge. In the left distance, bridge approaches will take the road just to the right of the freight cars spotted on the siding.
 Since I only had one good picture of the bridge, I had to estimate the dimensions and adjust them for the room I had on the railroad. The final length of each truss ended up at 76 scale feet and the roadway is 16 scale feet wide. Styrene shapes coupled with Central Valley bridge girders were used in the construction.
The cardboard hill had to be extended a bit to shape it properly for the bridge. Plaster cloth needs to be applied yet along with the rest of the scenery. The roadway also has to be attached to the top deck of the bridge.
The prototype supports for the bridge consisted of iron cassion piers filled with concrete. According to bridge pictures I found on line, these caissons were formed of sheet iron riveted into tubular sections running about four feet long. These were then riveted together to form the length of the pier needed. Sheets of iron were placed between the piers for stability and to prevent debris from catching on the piers. These were also formed of styrene parts. Archer rivet decals were used for the rivets and Bragdon weathering powder give the piers a slightly rusty appearance.
   Obviously, the bridge is not yet completed but enough is done so that the river valley can be scenicked. Once that is done, the bridge approaches will be built and everything installed.