An electric train can return energy to the traction system while braking. Another train can use some of it if that train is accelerating at the same time and the electrical connection can carry the power. Without such a match, the opportunity may be lost even though the braking train still produces energy.
Two multi-car trains brake and depart under several schedules. One timing arrangement misses the chance to share power; shifting a departure creates an overlap between energy production and use. A final case keeps the timing but limits the electrical path, showing why synchronization alone cannot guarantee full recovery. The comparison focuses attention on when energy is available, when it is needed, and whether it can reach the other train. That matters for timetable design and traction-power planning: a useful schedule can reduce grid energy demand without changing the basic train trips, but infrastructure sets a ceiling on the benefit.
A port has a limited length of quay, and a ship must occupy one continuous stretch of it for the duration of service. Assigning an arriving vessel to the first apparently open place can block another vessel that needs a different length or arrival window.
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Quay cranes are shared resources. Splitting them evenly between two ships may seem fair, yet keeping both ships in service longer can delay a third vessel that needs a berth. The time at which a ship leaves can matter more than how busy every crane appears at each instant.
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An inbound flight is late, and some passengers are trying to board a departing connection. Holding that outbound aircraft could save their trip, but it also delays the people already aboard and may cause new missed connections farther down the route.
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