Not every suicidal person has a therapist at hand when they may need one - They're far more likely to have a gun.. 
And, it's a tad harder to commit suicide by train; while knives and ropes are more labor-intensive and take more than an instantaneous act of will - both give the distraught just a tad more time to reflect and perhaps reconsider. Before guns became so common, automobiles seemed to play a more prominent suicide role (though i imagine it's still another easy-access  method- but guns tend to be more certain. I've had 2-3 friends/acquaintances over these many years choose to pick their own time and means to depart their earthly lives. For those relying on making rational life-terminating choices as their end-of-life time closed in,  there was/is the Hemlock Society - they provide discussion, one-on-one feedback and dialogue, and information.