I believe that everyone enjoys music in some from. Bringing organised music to subways could make them more welcoming and cause people to take time out to stop and listen. In New York most musicians are licensed to play underground through a program known as Music Under New York, which started in 1985 and is sponsored by the Metropolitan Transportation Authority. Every spring, 60 to 75 acts, chosen from about 200 audition tapes, try out before a panel of judges Grand Central Terminal; about two dozen of them are selected. The result is that more than 100 individuals and ensembles give 150 free performances every week at one of 25 belowground locations.
The people of Toronto took this even further by organising a 'Subway Dance Party' (I think this was befor the TMobile adverts) bringing people together to socialise. This led me to think of how people tend to avoid eye contact in the confined space of a subway train. A cities subway has the most fascinating mix of people from different cultures passing through it but we never find this out as we deliberately avoid contact. Why not designate one car as a 'Social Car' to get people talking? And perhaps a 'Quite Car' for journeys home from work after those particularly stressful day!