This 1935 cover image shows a tower under construction of the Triborough Bridge of New York City (now known as the RFK Bridge), a suspension bridge with a main extension of 1,380 feet, which connects the Queens County with Wards Island.
It marked the first use of a Derrick type with structural steel staging to perform this task. The 20 -foot 20 -foot staging tower was supported on the dock, and more than 200 feet was built in stages as steel erection continued.
The platform for the Derrick boy at the top of the staging presented Outrigger tube, which extends 38 feet in front and back to hold the type cables. The erecting Derrick had a 106 -foot pole and a 94 -foot boom, with a lifting capacity of 75 tons.
The Derrick remained occupied, first erecting the tower of the queens on the road, then dismantled and reassembled next to the Wards Island to achieve the same result, and then returned to the queens, at which point the steel of the Queens tower was riveted.
Once used to climb the 270 -foot queens tower, it was dismantled and reassembled on Wards Island to complete this tower. This maintained the construction of steel erection and filling work, improving safety for working crews.
