Minecart seem to collide with blocks weirdly and get stuck in stairs and slabs. They stop about 1/3 of a block away from full blocks. Furthermore if you quit a save and enter back into a world they will be even more displaced and will appear as if they are a block away from one end and glitch about 1/2 of a block on the other end of the railway. I have provided a  picture of my setup so you can replicate it.