I have three chest minecarts on a looped track. Two stations on track, one recieving, the other dispensing items. One minecart moving between stations, setting the next cart off as it arrives. This had been running fine all of the day before.

Minecraft crashed after laptop was in sleep mode and when I restarted it, the moving minecart had vanished. I checked the entire track several times. Track is indoors so no mobs are responsible.