Photograph by Francis Cooper (1874-1944) who lived 1898-1901 at 304 North Essex.
It appears in The World of Francis Cooper: Nineteenth-Century Pennsylvania Photographer by Jay Ruby (University Park, PA, Pennsylvania State University Press, 1999) under the title "Stone bridge", no location or date given. Because dozens of our Facebook followers agreed that the tunnel construction and topography very closely matches our tunnel, we feel confident in the attribution. The Narberth Community Library has a copy of Ruby's book.
Updated December 28, 2021.