That looks truly awful. But when you think about it there are so many people that still need to physically travel into work. Doctors and nurses obviously (and not just those dealing with corona related patients), lab technicians, phlebotomists, x-ray staff, chemo staff, dialysis staff etc etc. Plus hospital porters, hospital cleaners, hospital kitchen staff, hospital security. Outside the NHS - shop staff (ie supermarkets, chemists), warehouse staff, delivery drivers; utility company maintenance staff; transport staff; and loads others that are deemed key. Combine that with people still going to work because they can’t work from home but their employer hasn’t shut down operations yet so the government subsidy doesn’t come into play; self employed who have no extra help; and then transport companies running reduced services so all these key workers are cramming into fewer trains - it’s a recipe for disaster.