This bridge is at the northeast corner of Manhattan Island and allows Amtrak trains to go down the west side of the island to Penn Station. The route is being taken out of service this (2018) summer for repairs including this bridge. The mechanical and electrical equipment has corroded because of the 2012 super-storm Hurricane Sandy. The Empire Tunnel will also be reconstructed. During this outage, the Amtrak trains will terminate at Grand Central Terminal instead of Penn Station.
The Left Coast Lifter will be used to lift the movable span and place it on a barge so that the contractor can work on it offsite. See the Tappan Zee construction for some information on the Left Coast Lifter, one of the worlds largest floating cranes.
A 20X video of the lift
I selected nine of the photos that are on Amtrak's web site.
New life for an old bridge - The plan for rehabilitation of the Spuyten Duyvil Bridge was as follows: Replace large portions of the floor system and repair extensive portions of the trusses. Totally replace the center pivot and turntable structure. Rebuild the tops of .the existing river piers, and repair the existing timber fender system. Provide new electrical and mechanical operating systems. Clean and paint the bridge, lay new track, and open the line to rail traffic. The Contractor opted to perform much of the repair and replacement work off-site. Early in the Contract barges were brought to the site and the truss spans were removed from their piers and loaded onto the barges for shipment to a work yard in Kearny, New Jersey. The swing span was split into three pieces for shipment - two end trusses and center tower. Most of the steel repairs and new steel replacement parts were made in the Kearny work yard, and the cleaning and painting of the structures was also accomplished prior to reshipping the structure back to the site. The Contractor also arranged for some of the major mechanical components, such as the end wedges, to be mounted in the shop on the new structural steel supports. This certainly reduced some of the potential for coordination probiems between mechanical and structural trades which often times develop in movable bridge construction jobs. HeavyMovableStructures, p10
The Left Coast Lifter and the swing span on a barge (source)