Levee Gate
When building across rivers, the railroads wanted to minimize bridge heights to reduce construction costs and to keep the tracks as level as possible. Bridges over navigable rivers either had to be high enough to clear the river vessels, or a more costly bridge had to be con- structed that could be lifted or swung around to allow the vessels to pass through. Bridges had to be high enough to be above any expected river levels occurring during a flood, and as low as possible to minimize ap- proach grades. These considerations had resulted in an uneasy compromise over the years about how high to construct the bridge above the river. As the years passed and towns along the river flooded, levees were built to protect these towns; however, it was not feasible to raise the railroad tracks above the levees. Instead, the railroad bridge across the river was accommodated by making a break in the levee for the tracks. Provisions were made to put a barrier at the opening in the levee so that in the event of a flood the levee would protect the town from flooding. The barrier did not have to be wa- tertight since sandbags could be stuffed into any cracks to seal the leakage. Augusta, Georgia, has a levee to protect the buildings along the Savannah River from occasional flooding. Nor- folk Southern, formerly Southern Railway, has a bridge across the river at Augusta, and there is a levee on the town side of the river to protect the business district. The levee is basically a long embankment about 12 feet high sloped on both sides. The levee is landscaped since the river side is a greenbelt with walkways, benches, and boat docks.
An approximately 20-foot wide break in the levee ac- commodates Norfolk Southern’s track. The break is lo- cated only a few feet from the edge of the railroad truss bridge across the Savannah River. The opening is more than wide enough for the trains passing through it — the bridge is much narrower. The large gap allows mainte- nance vehicles to approach the bridge. Sheet metal pil- ing driven deep into the ground retains both sides of the levee break. The shaped sheet metal pilings interlock with each other to form a stiff, rigid wall that can both hold the levee and support and hold the railroad bar- rier. At the crown of the levee — at the maximum height — the pilings are lined up so long wooden timbers can be placed across the tracks to make a temporary wall in the event of a flood. The timbers lock into the “keyways” in the pilings and are placed on top of each other. At Augusta, the timbers are secured together in pairs and separated by an I-beam, which has lifting eyes. These
38 RAILROAD MODEL CRAFTSMAN
The levee is landscaped since it is in the downtown area, and there is a greenbelt with walkways, benches, and docks on the river side. Pedestrians along the top of the levee have to detour either under or across the tracks at this location. Note the slot in the center of the crown for the barrier.
eyes can be used to lift the timbers and to fasten the lift- ing eyes together when they block the tracks. In other instances, the levee break is made using con- crete or metal retaining walls, with a “keyway” in the le- vee wall for the temporary barrier across the tracks. The temporary wall across the opening can also be made us- ing a metal wall or a slab of concrete. The right-of-way is not maintained very high above the ground level. When the gate is placed in position, sand- bags, rocks, and dirt can be placed across the bottom of the timbers to block the water. Although the gate does not have to be watertight, it keeps out most of the water. The timbers are placed next to the levee break, conve- nient and easy to reach in the event of a flood. They can simply be lifted into place by a forklift or small crane us- ing the eyes for lifting and securing them to each other. Between the I-beams and preservative in the wood there is no chance that they will float away.
A levee with a break for the railroad tracks would be an interesting detail at a river crossing. The timbers can simply be made using spare ties glued together, and if you want, some structural pieces to hold them together. The wall can be made using other structural pieces, or it can be a concrete wall.
Thornton Waite
PERSPECTIVE
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