Fatigue is certainly among those factors. As I said, we put it on our watchlist of key safety issues. We have not issued any specific recommendations on that issue, but we have pointed out that it is a problem for freight train crews.
Regulations already require railway companies to have fatigue management plans, but those do not always take fatigue science into account. The matter is sometimes subject to negotiations between the unions and the employer.
However, many other factors can cause an accident. For example, an accident may occur after a misinterpreted signal, as may have been the case in Burlington. So some of the recommendations we made had to do with automated systems to stop trains if the crew is not responding to a signal correctly.