Steam is a different story, likely to be banned in the near future anyway, due to enviromental concerns, lack of PTC, and other reasons the Feds. now have a hard on for steam. Your comment about way to many in the cab is one. Steam, however, had more for the crew to do (run boiler, maintain fuel and fire, maintain flues, water issues and such, plus the unbearable noise some locomotives had) then modern diesels do, but at that, if you look at ICC accident reports, conversations in the cab were noted in the causes of several collisions due to missed signals.