Alanah, this is a great topic to explore and has broader applications beyond mental health. I can't provide access to plans and the like, but I can offer the following advice:

- you are attempting to design an intervention at the very critical moment in the person's decision-making. Changes to the environment can help, and you should consider clear links to services like Lifeline for people actively considering self-harm;

- we know that people in underground environments respond positively to the introduction of natural lighting, and living things such as plants, and also to water and natural sounds. Lighting and other techniques to minim natural environments are a reasonable backup plan;

- warm materials, such as wood and sandstone, can improve people's sense of calm and well-being

- increasing the oxygen content in the air, and vigorously reducing the levels of CO2 (a real problem in a busy, crowded, underground space like Town Hall station) can also help improve general sense of wellbeing.

Other things to consider:

- Town Hall is full of people, but that can actually contribute to a sense of loneliness and isolation. There are people everywhere, but you have no-one to talk to.

- Take a look at the new Metro platforms and the way in which the tracks are screened off. Doors only open when the train has arrived and reached a stop; there are no gaps between train and platform. 

Steve

Thank you, @Steve B,

Your point on Lifeline inclusion and possible solutions for loneliness is very interesting, and I will investigate this further to find ways I could integrate this into my designs. I have researched biophilic design inclusions in train stations and can't find many examples of living or moving elements in underground environments. I'll need to research further to see if it's feasible for Town Hall Station; however, sensory features, lighting or natural materials, like you pointed out, might be more maintainable. Thank you again for your advice; it will inform parts of my research and help with initial designs greatly. :)