I have already read math papers while standing in the tram. Not comfortable but possible (the same would, of course, hold for a train). Also depending on the ty

I have already read math papers while standing in the tram. Not comfortable but possible (the same would, of course, hold for a train). Also depending on the type of train it can be possible to answer emails on your mobile phone while standing (I don't own a mobile phone but have seen people doing that). Not all kind of work is done on a laptop or tablet. It can also be reading texts, checking emails etc. (of course you will try to optimize your schedule accordingly).