Minecarts play the sound of running on rails when it is not on rail but still has kinetic energy.
This bug can be reproduced by going to somewhere with mineshaft nearby and type this command: /tp @e[type=chest_minecart] ~ ~ ~
When this command springs into action, all chest minecarts in the mineshaft will be teleported to the player's current position and, since they have moved so quickly to achieve this, continue moving forward until they have to stop. But even after that, the sound of minecart running on rail would be played, endlessly looping.
I am sure this is a bug rather than a feature since this sound isn't recorded in the subtitles.
The situation I described above can be seen in the video I attached.