Cancel all trains?
Perhaps Southern should be commended for its recent efforts to reduce fatalities.
I'm not sure if your two statements are linked, though I assume they are. I do understand your point
but flippancy aside, Southern have made good steps to reducing suicide on their network, as broadly speaking it still has a high number of express trains but now a much more scattered and random rate of suicides as opposed to various hotspots (a couple of very specific stations aside, in the case of longer term analysis).
Although I can say from experience that every mental healthcare emergency will have its nuances and variations, there has been a huge amount of signage, fencing and lighting installed which does seem to have provided a mental block against suicide for some people, and there have recently been trials of various technological means of spotting people in distress. In addition, staff alerts for vulnerable people and overall awareness is pretty good, and there is a new internal hotline being rolled out for advice on assisting suicidal people on the railway. All this has joined together to provide a lot of resilient contingency planning which has really helped provide an anti-suicide culture and I do feel that it's worked. Of all the things Southern could be criticised for, this is not one of them.