From the Super Mario Wiki
The Container Yard is an outside area of the Old Clockworks in Luigi's Mansion: Dark Moon. The Container Yard is accessed by taking the second or third right doors inside of the Transportation Hall. The Container Yard is a large storage room. There are many huge crates stacked upon each other and a large red machine that dispenses Robombs when its chain is pulled. An extensive pulley system is set up in this room that is affected by the amount of bombs that have been dispensed. The two doors on the left lead back into the Transportation Hall.
During Roundhouse Brawl, Luigi must go through the Container Yard so he can reach the end of the Transportation Hall. When entering the room, the ramp is up. In order to lower the ramp, Luigi must pull the chain to drop a Robomb into a box connected to a pulley system. Dropping three bombs into the box lowers to the ramp so Luigi can cross. However, during this process, two Slammers attack Luigi. On the other side of the ramp, Luigi must detonate the bombs he dropped so he can cross the bridge. During Play Catch, the Polterpup enters the Container Yard, but immediately leaves when Luigi enters the room. Luigi has to make his way to the end of the room so he can ambush the Polterpup while it's not looking. During Outlandish Interruption, the Container Yard might be one of the rooms infested with ghosts.