Philipp Klein was a part-time switchboard operator in the SAM Lab while studying chemical engineering at Columbia University. As a relief switchboard operator, he worked mostly when the Lab was closed, but occasionally connected calls for the extension associated with Nobel Laureate Harold C. Urey to the outside world or to Long Distance. After the war, Klein went on to have a long scientific career with GE, NASA, and the Naval Research Laboratory. He specialized in solids, energy conversion, and crystal growth before retiring in 1990.
Klein submitted this story from his time on the Project:
"Some of the military personnel attached to the S.A.M. Labs also took courses in the Engineering School at Columbia University, where I was a full-time student. I became acquainted with several of them. Those who lived in Chicagoland liked to call home periodically. At the time, a three-minute phone call from New York to Chicago cost something like three dollars. However, by my use of tie lines to the Chicago part of the Manhattan Project, I could set these soldiers up with a local call to their families. For nearly 60 years, I have justified this unauthorized use of phone lines by saying that it certainly boosted morale and in no way obstructed the progress of the Manhattan Project."