What I expected to happen was...:
the minecart and powered minecart would stop making noise once stopped against the wall

What actually happened was...:
they didnt stop making noise untill the powered minecart ran out of fuel

Steps to Reproduce:
1. lay down a straight track of regular rails with walls at the ends
2. place a minecart and powered minecart on the track
3. power the minecart so it pushes the regular minecart into the wall