Stacked minecarts go forever if stacked on eachother. Originally found with chest minecarts and powered rails. I didn't found any of this reported yet so... I used a modded client but the bug is also in vanilla (tested). I attached a video with this bug it was too large, so i uploaded it on my website: http://tonkunservu.netau.net/Files/bugs/bug/bug.html
If the video stops during playback, it might still be uploading.
Environment
Windows 7, Minecraft, 1.5.1, Flat, Java Version 7 Update 17
Duplicate of MC-14, please use the search function to see if your bug has already been submitted. Currently over 55% of tickets are being closed as duplicate.