Well, the OP has probably seen these links already, but for others:
New Haven Terminal Locomotive Images
Images of the NHT railroad's locomotives, looks like they were still active in 1980 (i.e. several locomotives seem to be in service on active track with revenue freight cars, not parked rusting on a overground siding)
New Haven Terminal Today
Seems to mostly be a tank farm (not always a big user of rail service), but they also have several large dry-cargo warehouses. (Plus a pier and wharf space).
Two rail sidings, although I am not certain if they are active (they are listed as such, and I think there's a thread about them somewhere).
, same orientation as the view of NHT 10 (second image down on the Railroad Pictures Archive site linked above. Looks like that track NHT 10 is on has been paved over and put out of service.