I’m not sure that’s still enough passengers to make it viable. Most routes run all day and have 3 hr busy periods twice a day, whereas the arena and stadium is going to be mainly evenings. Trains aren’t the solution here for me as they are quite rigid in scheduling, requiring planning way ahead. Any new stations nearby need to be on an existing route - maybe that’ll be the case if GM can get it’s trains running better and have a service on that line but we’re years/decades from that. IMHO trams, buses, cars, taxis and walking are currently the best way to handle the large number of people.