Riding a saddled pig on a minecart no longer works to create a fast smooth, long distance ride on the rails. This is only nonfunctional when a player is riding the saddled pig in the minecart. If the saddled pig in the minecart is pushed down the rails it will still ride down the rails fast and smooth. If the player rides the saddled pig in the minecart the speed will be very uneven and choppy, but can still ride the full distance. This has been considered a long-standing feature that started as a bug, but seems that the interaction with the new attribute system may have made it unreliable. Confirmed by nyspace1 as well.