The study presented in this paper is placed in the context of accidents related to human factors mainly in terms of human errors. It presents both the current state of work about the concept of human stability and future developments that are planned. The objective of this paper is to show that this concept might make possible the anticipation of a human error or recovery from this one. To illustrate human stability concept, an example of train monitoring in the framework of ETCS (European Train Control System) development is applied