AH. This explains why my internet was so shitty yesterday. :p
somewhere, wikipedia has some amazing B&W 1910-1920 subway construction photos similar to this. this is the closest i could find
The one I'm looking for had about 20-30 pipes of varying size and direction/skew. What was particularly notable though was that they were using 20' long 12x12" rough hewn timbers, perfectly clear without a single knot in them as throwaway lumber for scaffolding that today would cost an absolute fortune and be better suited as a major crossbeam in some rich guy's vacation home.