They are 442 feet tall, weigh 1,600 tons, and move more efficiently than their predecessors.

Three new gigantic cranes, the tallest in North America, were hoisted in the port of Oakland on Thursday morning.

Port officials said it took weeks to assemble each of the massive cranes that arrived by tanker in December. The third was only completed last week. The port released a time-lapse video showing the cranes’ voyage from their arrival in the bay to their rearing Thursday.

The boom of each crane in the maintenance position is almost vertical at 442 feet and each weighs approximately 1,600 tons, officials said. The boom in its “stowed” position at a 45 degree angle is 372 feet high. The lifting height of the new cranes above the dock is 174 feet. Officials said that with larger cranes there is more flexibility to move the containers on and off a ship.

“These new cranes in Oakland will greatly improve the ability to move cargo more efficiently,” said Bryan Brandes, Port of Oakland’s maritime director, in a statement.

The raw video shows a ship with massive cranes as it entered San Francisco Bay under the Golden Gate Bridge destined for the port of Oakland on Wednesday morning.

Before being put into operation, the cranes undergo a series of tests and must be verified by OSHA. The first of the three cranes could be ready for use by the end of March or the beginning of April, port officials said.

The giant cranes were built in China by Shanghai Zhenhua Heavy Industries Co. and sent in sections on a ship to the port of Oakland. Longshore workers then rolled the cranes off the ship and an entire team of engineers and dock workers assembled the cranes on site in what officials called a very complex process.

All container cranes in the Port of Oakland are powered by electricity, so there are no local emissions according to official information.