Plate I in "The Interoceanic Problem and its Scientific Solution" by Elmer R. Corthell published by The American Association for the Advancement of Science, Ann Arbor, Michigan, 1885. It shows the pontoon and railway cradle. The original pamphlet is bound into Tracts 23 at page 252 held in the North of England Institute of Mining and Mechanical Engineers. It is uploaded with the permission of their librarian Jennifer Hillyard.