Mindfulness when on the train, underground and bus Many of us spend at least a couple of hours per day on public transport like bus, train or underground (for me it is around 2.5 hours).

How could we use that time to develop right mindfulness?
I too am on public transport for a reasonable part of the day. When I look around at my fellow passengers it's always notable to me how many are not present. The majority of people are on phones, checking social media, listening to music, flicking through a newspaper, doing anything but being present. It is rare to see people just sat there. This isn't to judge these people - commuting is tough particularly on some routes and people do what they feel they must do. 

But it's not just other people. I do it - listening to music, checking the phone etc... Recently I've challenged myself just to let go of these crutches to my commute. I don't listen to music etc.. etc.. I just sit there. I try to take notice. I wait and see what crazy thought pops into my head and try to spot where it came from. I try to be aware of my fellow commuters. I sometime play a game with myself where I wait and see how long it takes before I get bored. I never get bored. I get restless, frustrated but not bored.

Right now this is a good practice for me. My life is busy but I just add to it. There are moments in the day when I can take in a bit less information - commuting is one of them. Guarding the sense doors is an important (and difficult) practice for me. I truly believe that it's improved my mental state and is having a positive effect on my meditation practice. It's all conditions and if I spend my commute pumping extra information into my mind it's not surprising that at the end of the day I feel like I've poisoned my mind.

This answer is just my personal experience but I hope it's of some interest to you. Good luck with the practice on your commute.