To make it a legal requirement for all railway services - including those operating through the Channel Tunnel - to carry medical kits that contain both adult and child adrenalin auto-injectors, such as an Epipen.
You may be interested in these active petitions
I was shocked to read that this is not a requirement already. People with allergies will likely travel with their own adrenalin auto-injectors, but requiring all rail services carry these would help ensure they are available when required, and could help save lives.