This 4-car train of double deckers was on a fantrip on May 8 1971, and I was there. The train made a tour of electrified trackage, and this was the one and only time such stock traversed the Port Jeff branch.
The location shown is Robbins Lane, Syosset, where the Landia Plant of the Fairchlld Camera and Instrument Co was located. The station was built after Fairchild urged the LIRR to build halfway between Hicksville and Syosset.
Many of the employees lived in Queens near the old plant and commuted to this new plant, which consolidated everything under one roof.
Originally, 4 trains a day stopped there, but traffic dwindled as people moved to the Island. When the M1s and high level platforms (and third rail to this location) were coming, the station was abandoned rather than go to the expense of high platforms.
Caption data from Karl Groh; photo courtesy the Joe Testagrose collection