I also remember there being a siding for a quarry between Setauket and Port Jeff which saw freight service at present-day Skyline Materials on comsewogue road
until the 1980s. The siding has since been abandoned, and I'm not sure as to why [even though part of the track leading there can still be seen]. I'm also not sure as to why NYAR ended freight service to Port Jefferson in 2007, other than hearing something about freight cars becoming too heavy for the bridges and tracks between Northport and Port Jeff.
Lasltly, in the comment section of the video, I asked about freight operations on the Port Jefferson branch east of Kings Park, and I was told to go to trainsarefun.com, although I could not find anything specific other than what was listed on track maps for Port Jefferson. Does anyone happen to know some of the major industries served by the railroad between Smithtown and Port Jeff? I remember seeing a brick factory as one of the customers near the Port Jeff yard or wye, but I'm not sure if that's accurate.
"Look down, step over, and watch the gap!" - Dr. John Clarke, The Gap Rap (2010)