Hey Pickle,
Rotary dump is probaby your best option. You could also unload it with a crane, but you still have to clean the car. A text on bulk materials handling would probably cover the topic in more detail. You could also check the web sites of Svedala Dravo Wellman Company and FMC...
Just stumbled across your question. Yes, you can raise a railroad track. You have two choices: 1) Dismantle the track and reconstruct it at the new elevation; 2) Raise and tamp the track until you reach the desired elevation.
For a raise of 4-ft, the first option is probably the most...
