Updated description by GoldenHelmet
- Place a line of minecart track partly on top of regular blocks and partly on top of soul sand blocks.
- Send or ride a minecart down the track.
When the minecart travels over the soul sand, it slows down.
The soul sand has no effect on a minecart travelling above it.
On Bedrock 1.16.1 Soul Sand no longer slows down minecarts. I noticed this while riding my rollercoaster