Train emergency communication cords, what are your ethical opinions?

The person in control of the whole train is actually the guard and so she or he is on board the passenger cars to attend to whatever emergency may occur. The communication cord itself does not stop the train completely on its own, rather it makes what is called a partial brake application which is registered on the braking controls in both the engineer's cabin and the guard's compartment. Obviously, the procedure is then to complete the braking and bring the train to a halt. I believe that most modern communication cords have an intercom link with the engineer and guard as well. Ethically, these safety devices are not there to tell the train crew how to do their job, they are a rudimentary method of calling for help, rather the same as calling for the emergency services be telephone from a building etc etc. It's also worth remembering that (certainly on trains in Britain) there are considerable fines for "crank calling" on these devices!!