From what I can make out, there was a siding (more like a spur) that branched off the Montauk cutoff and, according to Bob Emery's notes, ALL sidings branching off the Montauk cutoff in this vicinity were referred to as "Kearney Sidings."
It curved around with various tracks branching off to service various warehouses. It crossed Borden Avenue eastbound at grade, went under the LIE and crossed Borden Avenue westbound at grade, right at the corner of 30th St. and Borden Ave.
The siding curved with another branching off and both crossed 30th St., entering the warehouse for Thypin Steel at the time. (Thypin Steel paralleled 30th Street.)
These sidings were installed in 1950 and Thypin Steel was built in 1950, so everything was probably built at the same time. One of the two sidings went completely through the Thypin Steel warehouse, crossing 30th place and servicing the Hiram Walker Co., new in 1956, then crossing 31st Place and servicing a roofing supply warehouse, Patterson Sergent Co. and Egleston Steel, eventually curving around and stubbing out at Borden Avenue again, just shy of Van Dam Street.
In 1955, additional sidings were installed branching off the two sidings entering Thypin Steel at 30th St. and headed back west again. They serviced Radio Engineering Co., Norge-York Appliance Co. and Standard Bag Corp.
Good 'nuff stuff?
Dave