Railfanning Photography

USC&G Benchmark C135 1947 on the DuSable Bridge in Chicago. Field Notes for Civil Engineers and Bridge Crews.

Article and photographs by Divi Logan with Assistance from Copilot Smart AI. 31 March 2026. Orientation of the northwest bridge tender's house as viewed from a window in the southwest bridge house (the museum location). 2 June 2019. On the foundation of the northwest house is the geodetic disc stamped C135 1947. 1. What is… Continue reading USC&G Benchmark C135 1947 on the DuSable Bridge in Chicago. Field Notes for Civil Engineers and Bridge Crews.