Loading/Unloading cars question

Let me ask you guys if it is possible to mod the transfer points to load / unload cars other than bulk ? Does it change the state of the bulk car to loaded/unloaded, and if so why not mod other cars to do the same. Boxes,tanks and so forth would just change weight and bulkheads with fixed loads to loaded /unloaded. I hope that makes a little sense. 
Well, I figured out the forklift ramp does load/unload the flat cars.
Now just figure out how to change from I-Beams to pipe.


Well, I figured out the forklift ramp does load/unload the flat cars.

Now just figure out how to change from I-Beams to pipe.
