American Society of Civil Engineers, by B. H. M. Hewett and W. L. Brown 42149 [Full title: Transactions of the American Society of Civil Engineers, Vol. LXVIII, Sept. 1910] [Full author: B. H. M. Hewett and W. L. Brown] [Subtitle: The New York Tunnel Extension of the Pennsylvania Railroad. The North River Tunnels. Paper No. 1155] [Link: http://www.gutenberg.org/4/2/1/4/42149 ] [Files: 42149.txt; 42149-8.txt; 42149-h.htm] Thanks to Juliet Sutherland, Martin Mayer and the Online Distributed Proofreading Team at http://www.pgdp.net David