The key players in this case were three BART engineers working on various aspects of the ATC:
Roger Hjortsvang, Robert Bruder, and Max Blankenzee.
The first to be employed by BART was Hjortsvang.
As part of his duties for BART, Hjortsvang spent 10 months in 1969-70 in Pittsburgh at the Westinghouse plant working with the engineers who were designing the ATC.
During this time, he became concerned about the lack of testing of some of the components of the ATC and also about the lack of oversight of Westinghouse by BART. After returning to San Francisco,Hjortvang began raising some of these concerns with his management.