Based on the theory of regulating activity, we present, discuss and analyze a labor and health problem which French train drivers have been facing for decades. We employ existing data available in the work of Le Guillant and Clot and take into due consideration the viewpoint of these authors, but - at the same time - we introduce complements and adjustments which we consider necessary for a deeper and more precise understanding of the problem under scrutiny. Our results relate to the dynamic development of human affect, emotions and feelings in (and out of) work. Our goal is to demonstrate that affect, emotions and feelings are inextricably bound to the dynamics of human activity, in a process of subjective development that is connected with the constant dialogic process of appropriation and (re)appropriation of tools - be they technical or semiotic - and that, for this reason, this process may involve serious issues not only of health but also of public safety.
Affect; Emotions; Feelings; Public Health; Public Safety