Construction of the subway tunnel at Broadway and 151st St ca 1905, NYPL
The NYC water system tunnel in Yonkers. NYPL
Tagged subway car (ca 1970)
"NYCS tagged IRT train" by JJ & Special K - http://www.flickr.com/photos/sweet_child_of_mine/452738765/. Licensed under Creative Commons Attribution-Share Alike 2.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:NYCS_tagged_IRT_train.jpg#mediaviewer/File:NYCS_tagged_IRT_train.jpg