One Panel at a Time.
New York City Transit Authority (NYCTA) Mantis crane no. 280 is seen on the business end of a work train assisting with track panel replacement east of Lorimer St Station on the BMT Jamaica Line. The 10-ton crane is one of 9 built by Thrall in 1989 under contract R102.
These "panel jobs" expedite track renewal by allowing track panels to be assembled in advance and installed in sections (aka panels). NYCTA's Linden Shop in Brownsville, Brooklyn produces track and switch panels, along with stocking other track maintenance materials like frogs and continuously-welded rail (CWR).
The process of installing the panels requires two work trains, one to remove old panels of track and one to bring in the new panels. The work trains are assisted by teams on the ground using cranes, typically from Bay Crane, to stage panels on closed streets below the el and lift them onto the structure where the work trains can then handle them. It is quite an interesting process to watch, especially if your train is delayed or running express because of it!