Derailed Minecarts that are clustered together often keep their movement speed, which is due to another bug (MC-14). In some cases (with the Minecart Improvements experiment enabled) if such clusters of minecarts are ridden by the player and collide with blocks, the screen goes black and the game stops working. It then has to be terminated manually.

Steps to reproduce (or use the link below for a more reliable method):

1. Place around 20 to 30 minecarts on a normal rail.
2. Push the minecarts. They should now start to move off the rail, keeping their velocity.
3. Ride one of the minecarts in the cluster.
4. Wait until it collides into blocks (2 blocks high is best). Water like in the attached videos isn't needed.

This is not very reliable, so a few attempts may be needed.

Alternatively, the attached world (MC-275883.zip) can be used to reproduce the bug:

1. Open the world.
2. Walk into the minecart cluster.
3. Ride one of the minecarts in the cluster.
4. Wait until it collides into the wall and locks the game.