Minecarts don't fall off a cliff and get stuck in a block

Look at screenshot.
What I did: put a minecart on one of these two rails
What should happen: minecart should fall
What happens: it loses momentum just before reaching the end of the track and sits on top of the block. Sometimes it falls a little bit lower and gets stuck in a block.
Also, if I put 2nd minecart, it pushes the first and first falls on the ground and gets stuck in a block.