ooh, I've got an question to !!SCIENCE!!: how does a loaded minecart (on rails and off) subjected to a cave-in react in comparison to other items? if it sruvives, as items sometimes do (not from a direct hit I don't think...), then will it maintain it's load, and if so, to what degree?
We also need to test how much protection, if any, they provide to items hauled within, especially when subjected to submersion in lava or water. Such as caged creatures or flammable items. I suspect they will open up a lot of possibilities for the !!SCIENCE!! of !!MATERIALS!! research, wherein materials and containers are subjected to heat in a fortress- or adventur-mode environment, due to the fact that there will be ways to move minecarts into and out of areas affected by magma and flames, whereas dwarves would die in the middle/carrying a burning object and ruining the experiment.