This instance appears to be not so much a case of attempted suicide as some clown playing chicken. I've been involved in this sort of situation several times. In the first instance, it was the same individual at the same location several trips in row. Once I realized this, I stopped even blowing the whistle at him, let alone applying the brakes. In another location, I made sure that when said individual(s) looked up at the cab as I went by, they would notice that I was paying no attention to them (I would be causally munching on a very large cinnamon roll, holding it high enough so that it was clearly visible through the cab window that I was nonchalantly snacking and paying them no heed). I both cases, the individuals quickly lost interest in their games because I was conveying the impression that I could care less whether they lived or died. Whether I actually cared or not was irrelevant because the message to be delivered was that I didn't, and this took all the wind out of their thrill seeking adventures. Train speed in both locations was 79 mph (127 kph).

It's a tricky business because if the E had not used emergency and this clown had been killed, the E could be charged (and possibly convicted of) manslaughter because he didn't employ all means at his disposal to avoid the mishap. Like it or not that's the way the legal system operates here in the States.

Applying the brakes in service and/or emergency, and how you do it, depends on the type of train you are operating.