I went looking through the Sanborn on line archive--here's a weird one--there are Sanborn fire insurance maps for 1904 and 1909 covering Central Bridge, but nothing later. Most other towns in the area have two more generations of maps going up into the 50s. Did Central Bridge become fireproof, or was it just considered expendible??
As of 1909, there were 5 tracks shown where the Rte 30A underpass is today (three tracks in 1904). It's ambiguous whether it's an underpass at that point, or a grade crossing. Also ambiguous as to what the other tracks were for.
Also shown are two sidings on the north side of the mains that diverged and went behind the passenger station and water tank. There's a lumber shed shown on one of them. There was an odd, gray building with an overhang standing in that location when I was a kid--got a couple of bad pix of it, not sure if that was the lumber shed or some later structure on the same site. I had heard it identified by locals as a milk loading facility.
As of the early 70s, there was a siding (maybe two) on the south side of the main that went way up past the freight house and beyond the main grade crossing to some sheds that stood in back of the (recently closed)village store, but it was in really rough shape. Had World War 1-era date nails in the ties, several of which are now in my collection. I never recall seeing it used, (except once to park a Sperry car at the freight house)--the locals just accessed the Richer mill from the north end switch every time I saw them.
The freight house had a Beacon Feeds sign on it for years, but I never saw it serviced by rail.
I heard some RR employees once tell me that the passenger station in town got taken out by a derailment in the mid 60s but I've never been able to confirm that.
Also of interest, Ed Hagen--the guy who wrote the book on the Schoharie Valley RR--said at a talk he gave to the Schoharie County Historical Society that the SVRR at one point (early on) did its interchange with the D&H at Central Bridge, by crossing the creek on the D&H main. I've never figured that one out--I've seen postcards of a depot at Schoharie Junction, but it looked like a farm house with a big window attached more than it looked like a station. Maybe the passengers got off at the Junction, but the freight interchange tracks were across the creek in Central Bridge??
Note this is wild speculation at this point (except for the Sanborn stuff--I have direct access to those) and I reserve the right to contradict myself in the future.