Duplicant Checkpoint

The Duplicant Checkpoint is an access-control building used to regulate Duplicant traffic through a corridor. When it is disabled, passing Duplicants stop at the checkpoint and wait in place until it is re-enabled, which makes it useful for holding workers at a bottleneck or staging them before a task. A very short enable signal is enough to release every Duplicant that has gathered there at once.

In practice, the checkpoint is most often combined with a Weight Plate or a Duplicant Motion Sensor to create a queue for buildings that must be used one at a time, such as Sinks, Ore Scrubbers, and similar facilities. A simple setup with only a checkpoint and a single trigger does not create a proper queue; the Duplicants merely stop together when the checkpoint is closed and then all pass through together when it opens again. To make orderly lines, the checkpoint needs to be part of a broader timing or occupancy-control setup.

The checkpoint also interacts with suit-based access. Duplicants will unequip Atmo Suits at this checkpoint and drop them on the ground if they pass through while suited, so it should be paired with an appropriate Atmo Suit Dock arrangement to avoid messy traffic flow. Its default behavior is to always allow passage, and when set this way a suited Duplicant returning through the checkpoint will still continue even if there is no empty suit dock behind it. If the checkpoint is set to only allow when empty, Duplicants will not pass when there is no vacant suit dock available behind the checkpoint, which is the safer choice when multiple suit routes exist in the colony.

There are a few important edge cases to keep in mind:

• If an area can be reached through both a Jet Suit Checkpoint and an Atmo Suit Checkpoint, Duplicants may sometimes pass the Atmo Suit Checkpoint without equipping the available suit.
• When used for suit access, a Duplicant may drop the suit on the floor if the checkpoint behind it is not configured to prevent passage without an open dock.
• Access restrictions can be applied through the checkpoint’s control behavior, allowing some buildings to be excluded from its rules by marking them as uncontrolled.

Overall, the Duplicant Checkpoint is a simple but effective traffic-management tool for colonists, especially when used to control building access, prevent workers from skipping service stations, or coordinate suit transitions at the edge of a base.