All Minecart Items can fit through upward-placed slabs

So if you build a mine cart track underground and try to make it 2 blocks from a wall or such, the Minecart won't be able to pass because it needs at least 3 areas of space. But if you put a slab on ton so it blends into the floor and seems to look like it could fit the mine cart through it no worries with tons of space left over. However this isn't the case and the Minecart will get stuck as if it is a full block. This should be changed to make Minecarts able to fit through upward-placed slabs. Otherwise, they just look weird not being able to fit.