Official trams, cable car and monorail systems, expanded metro, train and bus systems (More passenger info, more usage, more cars), a new screen for transportation which shows you the problems a train or car might face, as well as a screen for road connectivity issues and how helpful the line is for your road systems.
Usage of cargo trains to lessen the stress on industrial roads (If it exists, please explain to me how to do it)
If you have more suggestions, type them below!