Space sometimes gets tight on CTA’s Automated Guided Vehicles (AGV), when these are no longer transporting one 20-ft. container, but two at once. An improved terminal control system boosts productivity – and saves a large quantity of fuel.

This sensation only strikes one at second glance. Not until two 20-ft. containers are hanging simultaneously on the spreader and moving towards the ship, does it become clear that loading at CTA is now also done in the twin mode. The cooperation between three automated systems – gantry crane trolleys, automated guided vehicles (AGVs) and container storage blocks – is unique in the world.

Discharging in twin operation has long been a routine move in terminal processes. This involves simultaneously lifting two 20-ft. containers from a row 40 feet wide on the ship in one movement, with one AGV transporting these to the storage block and stacking them there. That is an effective way of emptying the ship’s hold.

The reverse direction requires two boxes from the Terminal Control System (TLS), that are initially assembled from one or more storage blocks before being carried punctually by AGV to the container gantry crane. From there the two small boxes are stacked together in a 40-ft. row in the ship. This routing may sound simple but called for more than two years of work for HHLA’s IT department. Equipped with IT architecture unique in the world, and several additional functions, the TLS now functions extremely flexibly in combining transport requirements.

For CTA this produces several crucial advantages: Speeding up of ship handling and shorter ship lay times, since with every move, the container gantry cranes lift twice as many boxes. The AGVs save fuel and CO₂ emissions, reducing wear and hence maintenance costs. The AGV fleet is optimally utilized: With fewer AGVs committed to transporting 20-ft. boxes, more vehicles are available for other transport requirements.

At CTA, twin handling is only one small step away from twin carrying. During loading, one AGV likewise transports two 20-ft. containers to the vessel but these are loaded successively rather than simultaneously. Even if only one 20-ft. row is available on the ship, therefore, when loading and discharging CTA also exploits all the advantages of improved AGV utilization. For CTA, one thing is clear: The double pack is the shape of the future.