Yes, given many rail staff have been trained in suicide recognition / prevention, surely better dealt with under the existing, well-recognised 'see it, say it, sorted' umbrella i.e. 'see something risky or odd, alert staff'.
I understand that won't always work quickly enough - but if it's meant to be quick enough for a bomb...
But back to my risk assessment; once you know what risks the broad category of 'men behaving oddly' present, you're also better able to identify who the appropriate people to encourage engagement with them would be. Like, just a guess... similar age men.