Haha. I remember switching that siding. Pascack Valley stone used the siding, not the small factory that was actually next to the siding. They got about a have dozen flat cars of large cut stone a year. It was a 2 car siding, and I actually remember we had 2 cars at one in there at one time. I have pix of the northern fromn the 1960's. Just have to figure out how to scan them,, Also have the closter station signs here
As for the CSX using part of the passing siding for the main, that was done during the conrail days, typical conrail lazyness in the track dept.
There was a switchback move into the the demarest lumber siding, that dated back prob to the 1930's. The tail track was in deplorable condition, so rather than fix it, the CR idiots used the north (west) end runaround switch as the demarest siding switch, and diverted the main into the siding. Then the main was diverted to run on the passing siding for a short stretch, and then s curved back to the main row. It was typical CR poor engineering. CR was the worst thing that happen to NE railroading, IMHO . 100% short term, we have to show a profit thinking. Ruined a lot of RR. Drove away a lot of customers, not the any of the class 1s are any better.