posted 12 years ago
Interesting picture of the rail car bridge, Saybian. The rail car is upside down! That pocket on the abutment is what the containers latch to. Very strong place, great idea. I'm retired now, but built bridges for a living in Southern California. The first critical issue with a bridge is it's span. If your span is less than 30 feet, a rail car is probably overkill. Plus you need fairly straight access for the rail car and access for a crane. I could never get a rail car down to our creek on the logging roads. The second issue is the load on the abutment. When the vehicle is over the abutment, the abutment must carry half the bridge load and all of the vehicle load without failing or sinking into the ground. Sinking is prevented by pilings or spread footings distributing the weight over a larger area. The area around my creek is clay, which seems very firm, but will ooze when wet and under load. If you have a way to pick up one end, you can add to your abutment to raise or level it if it sinks a little.
I was thinking of using 4x12s and 2x4 spacers with galvanized all thread on concrete abutments. That way I could assemble it at the crossing. I have to keep my abutments back from the creek. Our county/state are very strict about getting material in the creek bed.
I may be over doing this.... I built bridges for Caltrans in earthquake country!
P.S. Here in Northern California there are a lot of rail car bridges.