Tripwire/Minecart bug whilst trying to make automated minecart station

When making an automated minecart station (placing tripwires above the minecart to detect a player) i found that the tripwire will not set off when you get in, and the hooks will detach from the tripwire. When attempting to destroy it and rebuild it in the same place, the hooks will, again, detach from the tripwire. The automated minecart station can be found on SethBling's youtube channel.