I hopped in a minecraft and rode a track, that I made some time ago. When I arrived at the end of the track I wasn't able to leave the minecart or to hit it with a sword/bow or other items. I tried to ride back and to place water before me without success.. I had to place Lava to leave the cart but that killed me then.

Additional Observation: When I walked back the track to get the rails I broke with the water, they were gone. I'm 99% sure, that the despawn time wasn't over, though.

Steps to Reproduce:
1. Enter a minecart on powered rails.
2. Push a button for a trackselection; this button is not connected to the powered rail, but to a railway switch later on the track
3. Push the button to start the ride.