The non-passing gantry cranes arrangement is composed of two
identical gantry cranes (twin GC) that must maintain a minimal
safety distance from each other (Klein, 2011) and typically serve
one area of the yard (Saanen, 2011). The twin GC configuration
may occur with RMGCs and RTGCs. If the twin GC is automated,
we refer to the system as twin ASC. Twin GCs may collaborate by
using a (flexible) exchange zone. In this setting, for example, the
one crane could retrieve a container on one side of the yard and
move it to an exchange point. Then, the other crane could retrieve
this container from the exchange point and deliver it on the other
side. An example of a terminal that uses twin GC is the Euromax
terminal in the Port of Rotterdam, The Netherlands.